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At least 487 records · Page 27Linked to original sources
PubMed2002

Multimodal evaluation of risperidone for destructive behavior: functional analysis, direct observations, rating scales, and psychiatric impressions.

Risperidone, an atypical neuroleptic, has become a popular option for treating destructive behaviors of persons with developmental disabilities. A few studies have been conducted that evaluate the effects of risperidone on destructive behavior; however, none of these studies have combined objective measures with rating scales to evaluate the effects of risperidone on destructive behavior across home and clinical settings. This study evaluated the wide range of effects of risperidone on destructive behavior of 2 persons with developmental disabilities using weekly functional analysis sessions, daily observations, hourly home data, weekly rating scales, and monthly psychiatric impressions. Results indicate that risperidone does decrease destructive behavior and that, for the most part, all of the various measures yielded similar results.

Adult↗
PubMed1992

Functional analysis of a type IIB von Willebrand disease missense mutation: increased binding of large von Willebrand factor multimers to platelets.

Type IIB von Willebrand disease is an autosomal dominant bleeding disorder characterized by the selective loss of high molecular weight von Willebrand factor (vWF) multimers in plasma, presumably due to their abnormally increased reactivity with platelets. We and others have recently identified a panel of missense mutations clustered in the platelet glycoprotein Ib binding domain of vWF from patients with type IIB von Willebrand disease. We now report functional analysis of one of the most frequent type IIB missense mutations, Arg-543----Trp (vWF R543W). vWF from a human umbilical vein endothelial cell culture heterozygous for the vWF R543W mutation showed markedly increased binding of large vWF multimers to platelets in the presence of a low dose of ristocetin compared to vWF from a normal control culture. Recombinant vWF containing the vWF R543W mutation expressed in COS-7 cells also demonstrated increased binding of large vWF multimers. Mixed multimers obtained by cotransfection of mutant and wild-type cDNAs showed partial dominance of the vWF R543W mutation. Thus these data demonstrate that the vWF R543W mutation alone is sufficient to confer increased binding of large vWF multimers to platelets in a dominant fashion and that no other factors relating to vWF posttranslational processing or secretion in endothelial cells are required for this effect.

Binding Sites↗
PubMed1990

In vitro expansion of CD3/TCR- human thymocyte populations that selectively lack CD3 delta gene expression: a phenotypic and functional analysis.

Highly purified CD1-3-4-8- human thymocytes were obtained by panning techniques combined with cell depletion with antibody-coated magnetic beads. Most of these cells expressed cytoplasmic CD3 antigen, as assessed by mAbs known to react with the CD3 epsilon chain. After culture with low doses of PMA (0.5 ng/ml) and subsequent addition (at 24 h) of recombinant interleukin 2 (rIL-2; 100 U/ml) cells underwent extensive proliferation (40-60-fold of the initial cell input after 2 wk). The majority of the proliferating cells were CD3-TCR-. The remaining cells (5-40%) were represented by CD3+ TCR gamma/delta+ (BB3- A13+) cells. Further removal of CD3+ TCR-gamma/delta+ cells resulted in highly purified CD3- populations that further proliferated in culture with no substantial phenotypic changes. When CD3+ thymocytes were cultured under the same experimental conditions, only CD3+ TCR-alpha/beta+ cells could be detected, thus indicating that PMA did not affect the surface expression of the CD3/TCR complex, but rather induced preferential growth of CD3- thymocytes. Surface marker analysis of cultured CD3- thymocytes showed that they were homogeneously CD7+, whereas low proportions of cells expressed CD2 and CD8 antigens. Among the natural killer (NK) cell markers, CD56 was highly expressed by all cells, whereas CD16, CD57, CD11b, NKH2, and GL183 were absent. Importantly, these cells were different from peripheral NK cells, as 80-95% of them expressed cytoplasmic CD3 antigen. Functional analysis revealed a strong cytolytic activity against both NK-sensitive (K562) and NK-resistant (M14, Daudi) human target cells. In a redirected killing assay against the Fc gamma R+ P815 cells, mAbs specific for triggering molecules including CD3, CD2, and CD16 failed to augment target cell lysis, while a strong cytolytic effect was induced by PHA. In addition, PHA alone or in combination with PMA induced tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) (but not IL-2) production by CD3- thymocytes. Cloning of fresh CD1-3-4-8-thymocytes in the presence of PMA and rIL-2 resulted in CD3-CD56+ clones that displayed a pattern of cytolytic activity and lymphokine production similar to that of the polyclonal populations. Northern blot analysis of transcripts coding for CD3/TCR molecules revealed the presence of CD3 zeta, epsilon, and gamma transcripts, while CD3 delta was undetectable. Mature transcripts for both gamma and delta TCR chains could be detected, whereas no TCR-alpha mRNA and only a truncated (1.0 kb) form of TCR-beta mRNA were revealed.(ABSTRACT TRUNCATED AT 400 WORDS)

Antigens, CD↗
PubMed1993

[Factors influencing survival in patients with coronary heart disease. II. Multivariate logistic function analysis].

A group of 683 patients with the significant narrowing (> 70%) of at least one coronary vessel diagnosed by coronarography performed between 1976-1988 in the Institute of Cardiology in Warsaw was followed during one to seven years. Two hundred ninety of them were treated surgically, 393 non surgically. A multivariate logistic function (MLF) analysis of 10 variables is presented obtained from anamnesis and hemodynamic data and their significance upon survival after 2, 4 and 6 years. In the group treated non surgically the number of narrowed vessels was a factor independently significant after 2, 4 and 6 years. After 4 and 6 years the ejection fraction and the left ventricle end diastolic volume index were also significant. In the group treated surgically none of those were significant after 2 years. After 4 and 6 years anamnesis of arterial hypertonia was significant after 6 years also left ventricle end diastolic volume index. Coefficients calculated from multivariate logistic function analysis allow the calculation of probability of survival for an individual patient.

Adult↗
PubMed1993

A cost function analysis of residential services for adults with a learning disability.

Successive UK governments have pursued a policy of community care for people with learning disabilities which, in the past ten years, has led to a marked change in the nature of residential provision. Research evidence on the costs and quality of alternative forms of community provision is inconclusive and contradictory. It is therefore timely to consider whether or not community residential facilities have delivered the expected quality of service at appropriate cost. The paper presents the results of a cost function analysis of a random stratified sample of staffed community facilities in England excluding London. Both costs and quality of care were found to vary greatly amongst community residential facilities. The most important factors explaining differences in cost were case-mix factors relating to client age, dependency and length of stay. Facility characteristics such as the type of building, the internal layout and the structural quality were not significant. Quality of service measures such as the extent to which care-regimes were client orientated and made use of local community services were positively and significantly associated with costs. Type of provider had no impact on costs independent of differences in case-mix and quality of care with the exception of the private for profit sector which appeared less expensive than other agencies. The shortcomings of the methods and implications of these findings for policy makers are discussed.

Activities of Daily Living↗
PubMed2000

Expression and functional analysis of Apaf-1 isoforms. Extra Wd-40 repeat is required for cytochrome c binding and regulated activation of procaspase-9.

Apaf-1 is an important apoptotic signaling molecule that can activate procaspase-9 in a cytochrome c/dATP-dependent fashion. Alternative splicing can create an NH(2)-terminal 11-amino acid insert between the caspase recruitment domain and ATPase domains or an additional COOH-terminal WD-40 repeat. Recently, several Apaf-1 isoforms have been identified in tumor cell lines, but their expression in tissues and ability to activate procaspase-9 remain poorly characterized. We performed analysis of normal tissue mRNAs to examine the relative expression of the Apaf-1 forms and identified Apaf-1XL, containing both the NH(2)-terminal and COOH-terminal inserts, as the major RNA form expressed in all tissues tested. We also identified another expressed isoform, Apaf-1LN, containing the NH(2)-terminal insert, but lacking the additional WD-40 repeat. Functional analysis of all identified Apaf-1 isoforms demonstrated that only those with the additional WD-40 repeat activated procaspase 9 in vitro in response to cytochrome c and dATP, while the NH(2)-terminal insert was not required for this activity. Consistent with this result, in vitro binding assays demonstrated that the additional WD-40 repeat was also required for binding of cytochrome c, subsequent Apaf-1 self-association, binding to procaspase-9, and formation of active Apaf-1 oligomers. These experiments demonstrate the expression of multiple Apaf-1 isoforms and show that only those containing the additional WD-40 repeat bind and activate procaspase-9 in response to cytochrome c and dATP.

Adenosine Triphosphate↗
PubMed2024

Metagenome-based diversity and functional analysis of culturable microbes in sugarcane.

UNLABELLED: Sugarcane is a key crop for sugar and energy production, and understanding the diversity of its associated microbes is crucial for optimizing its growth and health. However, there is a lack of thorough investigation and use of microbial resources in sugarcane. This study conducted a comprehensive analysis of culturable microbes and their functional features in different tissues and rhizosphere soil of four diverse sugarcane species using metagenomics techniques. The results revealed significant microbial diversity in sugarcane's tissues and rhizosphere soil, including several important biomarker bacterial taxa identified, which are reported to engage in several processes that support plant growth, such as nitrogen fixation, phosphate solubilization, and the production of plant hormones. The Linear discriminant analysis Effect Size (LEfSe) studies identified unique microbial communities in different parts of the same sugarcane species, particularly Burkholderia, which exhibited significant variations across the sugarcane species. Microbial analysis of carbohydrate-active enzymes (CAZymes) indicated that genes related to sucrose metabolism were mostly present in specific bacterial taxa, including Burkholderia, Pseudomonas, Paraburkholderia, and Chryseobacterium. This study improves understanding of the diversities and functions of endophytes and rhizosphere soil microbes in sugarcane. Moreover, the approaches and findings of this study provide valuable insights for microbiome research and the use of comparable technologies in other agricultural fields. IMPORTANCE: This work utilized metagenomics techniques for conducting a comprehensive examination of culturable microbes and their functional characteristics in various tissues and rhizosphere soil of four distinct sugarcane species. This study enhances comprehension of the diversity and functions of endophytes and rhizosphere soil microbes in sugarcane. Furthermore, the methodologies and discoveries of this work offer new perspectives for microbiome investigation and the use of similar technologies in other agricultural fields.

Saccharum↗
PubMed2004

Purification, characterization and functional analysis of an endo-arabinanase (AbnA) from Bacillus subtilis.

Bacillus subtilis synthesizes at least one arabinanase encoded by the abnA gene that is able to degrade the polysaccharide arabinan. Here, we report the expression in Escherichia coli of the full-length abnA coding region with a His6-tag fused to the C-terminus. The recombinant protein was secreted to the periplasmic space and correctly processed by the E. coli signal peptidase. The substrate specificity of purified AbnA, the physico-chemical properties and kinetic parameters were determined. Functional analysis studies revealed Glu 215 as a key residue for AbnA hydrolytic activity and indicated that in addition to AbnA B. subtilis secretes other enzyme(s) able to degrade linear 1,5-alpha-l-arabinan.

Amino Acid Sequence↗
PubMed2002

Functional analysis of the C6 zinc finger gene pro1 involved in fungal sexual development.

The pro1 gene, controlling fruiting body development in the homothallic ascomycete Sordaria macrospora, encodes a C6 zinc finger protein with a typical DNA binding domain of GAL4-like C6 zinc finger proteins as well as a putative nuclear targeting signal. In the corresponding mutant pro1, the pro1 gene is deleted, and the transition of primordia into mature fruiting bodies is prevented. To further characterize the PRO1 polypeptide, the yeast system was used for identifying a transactivation domain in the N-terminal half of PRO1, which probably also functions in S. macrospora. The functional analysis was extended by using truncated versions of the pro1 gene in complementation transformations of a deltapro1 mutant. Interestingly, the 5' part of the pro1 gene encoding the DNA binding and transactivation domain as well as putative nuclear targeting signals was sufficient to restore fertility in the sterile pro1 mutant. In vitro mutagenesis verified that the DNA binding domain is essential for normal fruiting body development. This was concluded from transformation experiments with eight pro1 derivatives containing triplet substitutions in conserved codons of the DNA binding domain; some, but not all, failed in restoring the wild-type phenotype in mutant pro1. Using a PCR-based cloning strategy, pro1 homologs from the two related heterothallic species Neurospora crassa and Sordaria brevicollis were isolated, showing similarities in the predicted amino acid sequences of 91 and 90%, respectively. When a N. crassa pro1 cDNA clone was used in complementation transformations, we succeeded in restoring the wild-type phenotype to the S. macrospora pro1 mutant. These data suggest that pro1 homologs from heterothallic species can provide the pro1 function in homothallic ascomycetes. Based on the published sequence of the N. crassa genome, we identified hpro1A, another transcriptionally expressed gene, with a similarity of 40% to the pro1 genes, which is present as a single copy gene in N. crassa as well as in S. macrospora.

Amino Acid Sequence↗
PubMed2003

Functional analysis of the interaction of the human immunodeficiency virus type 1 Rev nuclear export signal with its cofactors.

Human immunodeficiency virus type 1 (HIV-1) Rev-mediated nuclear export of viral RNAs involves the interaction of its leucine-rich nuclear export sequence (NES) with nuclear cofactors. In yeast two-hybrid screens of a human lymph node derived cDNA expression library, we identified the human nucleoporin Nup98 as a highly specific and potent interactor of the Rev NES. Using an extensive panel of nuclear export positive and negative mutants of the functionally homologous NESs of the HIV-1 Rev, human T cell leukemia virus type 1 (HTLV-1) Rex, and equine infectious anemia virus (EIAV) Rev proteins, physiologically significant interaction of hNup98 with the various NESs was demonstrated. Missense mutations in the yeast nuclear export factor Crm1p that abrogated Rev NES interaction with the XXFG repeat-containing nucleoporin, Rab/hRIP, had minimal effects on the interaction of GLFG repeat-containing hNup98. Functional analysis of Nup98 domains required for nuclear localization demonstrated that the entire ORF was required for efficient incorporation into the nuclear envelope. A putative nuclear localization signal was identified downstream of the GLFG repeat region. Whereas overexpression of both full-length Nup98 and the amino-terminal GLFG repeat region, but not the unique carboxy-terminal region, induced significant suppression of HIV unspliced RNA export, lower levels of exogenous Nup98 expression resulted in a relatively modest increase in unspliced RNA export. These results suggest a physiological role for hNup98 in modulating Rev-dependent RNA export during HIV infection.

Active Transport, Cell Nucleus↗
PubMed2002

Mutational spectrum in the PEX7 gene and functional analysis of mutant alleles in 78 patients with rhizomelic chondrodysplasia punctata type 1.

Rhizomelic chondrodysplasia punctata (RCDP) is a genetically heterogeneous, autosomal recessive disorder of peroxisomal metabolism that is clinically characterized by symmetrical shortening of the proximal long bones, cataracts, periarticular calcifications, multiple joint contractures, and psychomotor retardation. Most patients with RCDP have mutations in the PEX7 gene encoding peroxin 7, the cytosolic PTS2-receptor protein required for targeting a subset of enzymes to peroxisomes. These enzymes are deficient in cells of patients with RCDP, because of their mislocalization to the cytoplasm. We report the mutational spectrum in the PEX7 gene of 78 patients (including five pairs of sibs) clinically and biochemically diagnosed with RCDP type I. We found 22 different mutations, including 18 novel ones. Furthermore, we show by functional analysis that disease severity correlates with PEX7 allele activity: expression of eight different alleles from patients with severe RCDP failed to restore the targeting defect in RCDP fibroblasts, whereas two alleles found only in patients with mild disease complemented the targeting defect upon overexpression. Surprisingly, one of the mild alleles comprises a duplication of nucleotides 45-52, which is predicted to lead to a frameshift at codon 17 and an absence of functional peroxin 7. The ability of this allele to complement the targeting defect in RCDP cells suggests that frame restoration occurs, resulting in full-length functional peroxin 7, which leads to amelioration of the predicted severe phenotype. This was confirmed in vitro by expression of the eight-nucleotide duplication-containing sequence fused in different reading frames to the coding sequence of firefly luciferase in COS cells.

Alleles↗
PubMed1993

Phenotypic and functional analysis of mucosal T cells isolated from tissue explants of rat upper respiratory tract.

It has been hypothesised that T cells play a central role in the pathogenesis of asthma which is characterised by chronic inflammation of the airways. In order to further study the T cells identified in situ in the airways we have developed, in the rat, a novel method for the extraction of T cells directly from the airway mucosa. The T cells actively migrate from explant tissue under the influence of exogenous IL-2 yielding sufficient cells for phenotypic and functional analysis. The T cells obtained represent a random selection of cells present at the start of culture as determined by dot blot analysis of the T cell receptor. The majority of cells were CD8+ and did not express the alpha/beta T cell receptor. In addition, the cloning efficiency of the explant T cells was extremely low (1:28) compared to that of splenic T cells (1:2) in agreement with our earlier studies on peripheral lung T cells which also demonstrated a reduced proliferative capacity. This data suggests a generalised 'immunosuppressive' milieu throughout the respiratory tract.

Animals↗
PubMed1997

Molecular, genetic, and functional analysis of homozygous C8 beta-chain deficiency in two siblings.

UNLABELLED: C8 deficiency is associated with an increased susceptibility to neisserial infections. We present a case of an 11 year old boy who suffered from infection with Neisseria meningitidis. Medical history of the patient and his family (n = 5) did not indicate any previous immunodeficiency symptoms. Results from the analysis of phagocyte and lymphocyte functions were within the normal range. No hemolytic activities of the classical (CH50) and the alternative (APH50) pathways of complement were measurable, and SC5b-9 protein complexes could not be detected in the patient's plasma. Further analysis by highly sensitive ELISA and functional assays revealed a complete deficiency of C8. Upon the reconstitution with purified C8 total hemolytic activity could be restored. SDS-PAGE and Western blot analysis established a deficiency of the C8 beta chain. Genetic analysis at the genomic DNA level demonstrated the common C-T mutation in exon 9 of the C8B gene. Family analysis presented the older sister with non-detectable function of C8 in serum, both parents with about half-normal C8 titres, and the younger sister with normal C8 function. The parents and both sisters were asymptomatic, although the older of the sisters presented with the same complete C8 beta-chain deficiency as the patient described. IN CONCLUSION: the common C-T mutation in the C8B genes is the genetic basis of C8 beta-chain deficiency in two members of this Bosnian family.

Alleles↗
PubMed1996

Molecular cloning and functional analysis of a novel macrolide-resistance determinant, mefA, from Streptococcus pyogenes.

Several streptococcal strains had an uncharacterized mechanism of macrolide resistance that differed from those that had been reported previously in the literature. This novel mechanism conveyed resistance to 14- and 15-membered macrolides, but not to 16-membered macrolides, lincosamides or analogues of streptogramin B. The gene encoding this phenotype was cloned by standard methods from total genomic digests of Streptococcus pyogenes 02C1064 as a 4.7 kb heterologous insert into the low-copy vector, pACYC177, and expressed in several Escherichia coli K-12 strains. The location of the macrolide-resistance determinant was established by functional analysis of deletion derivatives and sequencing. A search for homologues in the genetic databases confirmed that the gene is a novel one with homology to membrane-associated pump proteins. The macrolide-resistance coding sequence was subcloned into a pET23a vector and expressed from the inducible T7 promoter on the plasmid in E. coli BL21(DE3). Physiological studies of the cloned determinant, which has been named mefA for macrolide efflux, provide evidence for its mechanism of action in host bacteria. E.coli strains containing the cloned determinant maintain lower levels of intracellular erythromycin when this compound is added to the external medium than isogenic clones without mefA. Furthermore, intracellular accumulation of [14C]-erythromycin in the original S. pyogenes strain was always lower than that observed in erythromycin-sensitive strains. This is consistent with a hypothesis that the gene encodes a novel antiporter function which pumps erythromycin out of the cell. The gene appears to be widely distributed in S. pyogenes strains, as demonstrated by primer-specific synthesis using the polymerase chain reaction.

Bacterial Proteins↗
PubMed2006

Functional analysis of the split Synechocystis DnaE intein in plant tissues by biolistic particle bombardment.

The DnaE intein of Synechocystis sp. PCC6803 (Ssp DnaE intein) is the first split intein identified in nature. Its N-terminal fragment (Int-n) is attached to the end of the N-terminal half of the DnaE protein (DnaE-n) to form the precursor DnaE-n/Int-n, while the C-terminal fragment (Int-c) precedes the C-terminal half of the DnaE protein (DnaE-c) to form the precursor Int-c/DnaE-c. Int-n and Int-c fragments in the separate precursors catalyze, in concert, a protein trans-splicing process to splice the flanking DnaE-n and DnaE-c into a functional catalytic subunit of DNA polymerase III. They then release themselves from the precursors. Previously, the Ssp DnaE intein has been used to reconstitute a protein trans-splicing mechanism in stably transformed Arabidopsis thaliana, resulting in successful reassembly of an intact and functional GUS from two halves of a split GUS protein. In this report, transient expression using a biolistic particle bombardment approach is described for functional analysis of Ssp DnaE intein. Analyses confirmed that the Ssp DnaE intein could catalyze protein trans-splicing not only in model plants but also in monocot and dicot crops. It also demonstrated that when up to 45 amino acid residues were removed from the C-terminus of the Int-n fragment, the Int-n fragment was still able to function in the protein trans-splicing process.

Amino Acid Sequence↗
PubMed1990

[Cloning and structural-functional analysis in Escherichia coli of genes of glutamate-producing corynebacteria controlling biosynthesis of amino acids of aspartic acid series].

A library of EcoRI DNA fragments from Brevibacterium flavum was constructed using plasmid vector. The genes complementing ThrA2 and ThrB mutations in Escherichia coli were identified in the library. The gene thrA2 of B. flavum codes for mutant enzyme homoserine dehydrogenase insensitive to inhibition by threonine. The genes thrA2 and thrB are localized wihtin the EcoRI fragment 4.1 kb long and are expressed under the control of their own promoters in E. coli cells. Structural and functional analysis of cloned C. glutamicum gene ilvA was performed. The gene of C. glutamicum complemented ilvA mutation in E. coli and appeared to be localized within the EcoRI--SacI DNA fragment 1.6 kb in size. Using E. coli minicells we have demonstrated that the gene ilvA of C. glutamicum controls the synthesis of polypeptide of relative molecular mass 50 kD.

Aspartic Acid↗
PubMed2002

Structure-function analysis of the glucose-6-phosphate transporter deficient in glycogen storage disease type Ib.

Glycogen storage disease type Ib (GSD-Ib) is caused by a deficiency in the glucose-6-phosphate transporter (G6PT), a 10 transmembrane domain endoplasmic reticulum protein. To date, 69 G6PT mutations, including 28 missenses and 2 codon deletions, have been identified in GSD-Ib patients. We previously characterized 15 of the missense and one codon deletion mutations using a pSVL-based expression assay. A lack of sensitivity in this assay limited the discrimination between mutations that lead to loss of function and mutations that leave a low residual activity. We now report an improved G6PT assay, based on an adenoviral vector-mediated expression system and its use in the functional characterization of all 30 codon mutations found in GSD-Ib patients. Twenty of the naturally occurring mutations completely abolish microsomal G6P uptake activity while the other 10 mutations, including 5 previously characterized ones, partially inactivate the transporter. This information should greatly facilitate genotype-phenotype correlation. We also report a structure-function analysis of G6PT. In addition to the 3 destabilizing mutations reported previously, we now show that the G50R, C176R, V235del, G339C and G339D mutations also compromise the G6PT stability. Mutation analysis of the amino-terminal domain of G6PT shows that it is required for optimal G6P uptake activity. Finally, we show that degradation of both wild-type and mutant G6PT is inhibited by a potent proteasome inhibitor, lactacystin, demonstrating that G6PT is a substrate for proteasome-mediated degradation.

Acetylcysteine↗
PubMed1998

Structure-function analysis of a conserved aromatic cluster in the N-terminal domain of human epidermal growth factor.

The importance of a cluster of conserved aromatic residues of human epidermal growth factor (hEGF) to the receptor binding epitope is suggested by the interaction of His10 and Tyr13 of the A-loop with Tyr22 and Tyr29 of the N-terminal beta-sheet to form a hydrophobic surface on the hEGF protein. Indeed, Tyr13 has previously been shown to contribute a hydrophobic determinant to receptor binding. The roles of His10, Tyr22 and Tyr29 were investigated by structure-function analysis of hEGF mutant analogues containing individual replacements of each residue. Substitutions with aromatic residues or a leucine at position 10 retained receptor affinities and agonist activities similar to wild-type indicating that an aromatic residue is not essential. Variants with polar, charged or aliphatic substitutions altered in size and/or hydrophobicity exhibited reduced binding and agonist activities. 1-Dimensional 1H NMR spectra of high, moderate and low-affinity analogues at position 10 suggested only minor alterations in hEGF native structure. In contrast, a variety of replacements were tolerated at position 22 or 29 indicating that neither aromaticity nor hydrophobicity of Tyr22 and Tyr29 is required for receptor binding. CD spectra of mutant analogues at position 22 or 29 indicated a correlation between loss of receptor affinity and alterations in hEGF structure. The results indicate that similar to Tyr13, His10 of hEGF contributes hydrophobicity to the receptor binding epitope, whereas Tyr22 and Tyr29 do not appear to be directly involved in receptor interactions. The latter conclusion, together with previous studies, suggests that hydrophobic residues on only one face of the N-terminal beta-sheet of hEGF are important in receptor recognition.

Circular Dichroism↗