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Biomedical subjects

M Odaka

Publications and source records attributed to M Odaka.

At least 73 records · Page 4Linked to original sources
PubMed1994

Tyr-341 of the beta subunit is a major Km-determining residue of TF1-ATPase: parallel effect of its mutations on Kd(ATP) of the beta subunit and on Km(ATP) of the alpha 3 beta 3 gamma complex.

Residue Tyr-341 of the F1-ATPase beta subunit from a thermophilic Bacillus strain, PS3, was mutagenized to leucine, cysteine or alanine. Each of the mutated beta subunits was isolated and its affinity for ATP-Mg was examined by means of difference circular dichroism and differential titration calorimetry. The Kd values for ATP-Mg obtained were: beta Y341 (wild type), 0.015 mM; beta Y341L, 0.7 mM; beta Y341C and beta Y341A, > 3 mM. All the mutant beta subunits could be reconstituted into the alpha 3 beta 3 gamma complex with alpha and gamma subunits. The alpha 3 beta (mutant)3 gamma complexes hydrolyzed ATP with apparent Vmax values larger than that of the alpha 3 beta (WILD)3 gamma complex. The apparent Km values of the alpha 3 beta (mutant)3 gamma complexes increased in parallel with the Kd values for ATP-Mg of the isolated mutant beta subunits. These results indicate that residue beta Y341 is directly involved in the catalytic ATP-Mg binding and is a major Km-determining residue of F1-ATPase.

Adenosine Triphosphate↗
PubMed1994

[Möbius syndrome with crossed total hemiatrophy--a case report].

The patient was a 26-year-old male who was noted to have asymmetry on the face, upper limbs, and trunk, and who showed no pursuit eye movements and no changes in the facial expression from birth. The patient developed transient global amnesia and was hospitalized. Neurological examination established atrophy of the right face, and left trunk involving the upper limb, and bilateral oculomotor and abducens nerve palsy. In auditory brainstem response, waves III to V were bilaterally obscured, and the blink reflex disclosed disturbances of peripheral facial nerve and the brainstem, suggesting developmental abnormalities of the facial motor nucleus. Contralateral R1 was also recorded in the blink reflex, and crossed trigeminofacial pathway was suspected. Möbius syndrome is associated with various muscle and skeletal abnormalities, but the coexistence of crossed total hemiatrophy has not been reported. We think that our case might be the first case of Möbius syndrome with total hemiatrophy.

Abnormalities, Multiple↗
PubMed1993

In vivo affinity label of a protein expressed in Escherichia coli. Coenzyme A occupied the AT(D)P binding site of the mutant F1-ATPase beta subunit (Y307C) through a disulfide bond.

When Tyr-307 of the beta subunit of F1-ATPase from a thermophilic Bacillus strain PS3 is replaced by cysteine and expressed in Escherichia coli cells, about a half population of the mutant beta subunit are labeled by Coenzyme A at Cys-307 through a disulfide bond which is cleavable by reducing treatment. The mutant beta subunit can be reconstituted into the alpha 3 beta 3 complex of which ATPase activity is stimulated two-fold by reducing treatment either prior or after reconstitution. Since Tyr-307 has been supposed to be located at one of subdomains which form the ATP binding site of the beta subunit, Coenzyme A binds to the mutant beta subunit as an AT(D)P analogue in E. coli cells and then covalently attaches to Cys-307.

Adenosine Diphosphate↗
PubMed1993

AT(D)PMg-induced dissociation of the alpha 3 beta 3 complex of the F1-ATPase from a thermophilic Bacillus PS3 into alpha 1 beta 1 heterodimers is prevented by mutation beta (Y341C).

AT(D)PMg induces dissociation of the alpha 3 beta 3 complex of F1-ATPase from a thermophilic Bacillus strain. PS3, into the alpha 1 beta 1 heterodimers [(1991) Biochim. Biophys. Acta 1056, 279-284] but the location of the AT(D)PMg binding site responsible is not known. From the analysis of AT(D)PMg binding properties of the isolated mutant beta subunit, beta(Y341C), and the stability of the alpha 3 beta(Y341C)3 complex in the presence of AT(D)PMg, we conclude that binding of AT(D)PMg to the Tyr-341 site of the beta subunit(s) in the alpha 3 beta 3 complex triggers the dissociation of the alpha 3 beta 3 complex into the alpha 1 beta 1 heterodimers.

Adenosine Diphosphate↗
PubMed1993

Solution structure of the SH3 domain of phospholipase C-gamma.

SH3 (Src homology 3) domains are found in many signaling proteins and appear to function as binding modules for cytoplasmic target proteins. The solution structure of the SH3 domain of human phospholipase C-gamma (PLC-gamma) was determined by two-dimensional 1H NMR analysis. This SH3 domain is composed of eight antiparallel beta strands consisting of two successive "Greek key" motifs, which form a barrel-like structure. The conserved aliphatic and aromatic residues form a hydrophobic pocket on the molecular surface, and the conserved carboxylic residues are localized to the periphery. The hydrophobic pocket may serve as a binding site for target proteins. Analysis of the slowly exchanging amide protons by NMR measurements indicates that despite containing a high content of beta structure, the SH3 domain of PLC-gamma is flexible.

Amino Acid Sequence↗
PubMed1993

A 40-kDa epidermal growth factor/transforming growth factor alpha-binding domain produced by limited proteolysis of the extracellular domain of the epidermal growth factor receptor.

Elucidation of the three-dimensional structure of the complex of the epidermal growth factor (EGF) and its receptor is essential for understanding the molecular mechanisms of the EGF-receptor interaction and EGF-induced receptor-receptor interaction. NMR is useful to investigate interactions in solution between macromolecules at atomic resolution, but has a limitation in molecular masses of target proteins: less than 300 residues. We have prepared a fragment with apparent molecular mass of 40 kDa in SDS gels from the soluble extracellular domain of the EGF receptor (sEGFR, 619 residues) by sequential limited proteolysis with proteinase K and bromelain. This fragment is a monomeric structural domain consisting of 202 amino acid residues (Cys302-Arg503) and 18-kDa sugar chains, and binds EGF and transforming growth factor-alpha (TGF alpha). This 40-kDa domain has a dissociation constant of about 1 microM for human TGF alpha, which is similar to that of the parental sEGFR. sEGFR oligomerizes in response to EGF and TGF alpha, while the 40-kDa domain does not, suggesting that the sequences other than this domain is required for receptor oligomerization. The 40-kDa ligand-binding domain described in this report is suitable for analysis by various physico-chemical approaches such as NMR.

Amino Acid Sequence↗
PubMed1992

Molecular dissection of the beta subunit of F1-ATPase into peptide fragments.

Partial digestion of the native beta subunit of F1-ATPase from the thermophilic Bacillus strain PS3 by three different proteases produced a limited number of peptide fragments. In most cases, the peptides remained associated, and the gross structure of the beta subunit was not destroyed. Furthermore, most peptides were able to reassociate into the form of the beta subunit after denaturating urea treatment. Therefore, the cleaved sites are most likely located in water-exposed loop regions in the tertiary structure of the protein. Almost all peptides were analyzed, and 17 cleaved sites were determined. From the analysis of the distribution of cleaved sites and deletions or insertions in the multiple amino acid sequence alignment of proteins homologous to the beta subunit, locations of five loops and four candidate loops in the beta subunit are suggested. There are two large loops in the central region of the beta subunit sequence, and dicyclohexylcarbodiimide-reactive Glu190 is located in one of them. Tyr341, involved in putative catalytic ATP binding, is also found in one of the loops. Then, taking cleaved sites as a reference, two kinds of expression plasmids, each of which carried genes of two complementary peptide fragments, 1-193 and 198-473 or 1-284 and 285-473, were constructed and expressed in Escherichia coli. For each plasmid, two peptides were coexpressed, associated into a stable beta subunit form in E. coli cells, and purified without dissociation. When these beta subunits were denatured by urea and applied to polyacrylamide gel without denaturant, a protein band with the same mobility as that of the beta subunit appeared, indicating that reassociation of peptide fragments into the form of the beta subunit occurred upon removal of urea. These beta subunits retained the ability to reconstitute the alpha 3 beta 3 gamma complexes even though the efficiency of reconstitution and the recovered ATPase activities were decreased. These complexes were stable at high or low temperature, and ATPase activities were sensitive to inhibition by N3-.

Amino Acid Sequence↗
PubMed1992

Single site hydrolysis of 2',3'-O-(2,4,6-trinitrophenyl)-ATP by the F1-ATPase from thermophilic bacterium PS3 is accelerated by the chase-addition of excess ATP.

The interaction of 2',3'-O-(2,4,6-trinitrophenyl)-adenosine 5'-triphosphate (TNP-ATP) and TNP-ADP to F1-ATPase from a thermophilic bacterium PS3 (TF1) was investigated. When TNP-ADP or TNP-ATP was added to the isolated alpha or beta subunit of TF1, characteristic difference spectra were generated for each subunit. Difference spectra generated on addition of these analogs to TF1 resembled those observed for the beta subunit, indicating TNP analogs bind to the beta subunits in the molecule of TF1. Results of equilibrium dialysis showed that TNP-ADP binds to a single high affinity site on TF1 in the presence of Mg2+ with a dissociation constant of 2.2 nM. When TNP-ATP was added to TF1 in a substoichiometric molar ratio, it rapidly bound to TF1 and was slowly hydrolyzed. The hydrolysis proceeded nearly to completion without showing stable equilibrium between bound species of TNP-ATP and TNP-ADP. Similar to beef heart mitochondrial F1, this hydrolysis was greatly accelerated by the chase-addition of 100 microM ATP. However, the hydrolyzed product, TNP-ADP, remained bound on the beta subunit even after the chase.

Adenosine Diphosphate↗
PubMed1991

Clinical experience of double filtration plasmapheresis for drug refractory neurological diseases.

The effect of therapeutic double filtration plasmapheresis (DFPP) was clinically investigated for drug refractory neurological disorders. DFPP therapy was performed 181 times for 10 patients who were treated with medical therapy of steroid or immunosuppressive drugs without any improvement of their symptoms. After the induction of DFPP therapy the neuromuscular disturbances were soon ameliorated in 9 cases of them. After DFPP, serum levels of IgG, IgA or IgM were decreased as follows: IgG 0.53 +/- 0.16; IgA 0.60 +/- 0.11; IgM 0.59 +/- 0.09 (M +/- SD). After the DFPP therapy there was no relapse in improved 9 cases. But we could not regard the immunologic markers as the index of efficacy of DFPP. Because serum levels of IgG, IgA or IgM showed a tendency to decrease by using drugs, when we didn't observe any improvement of symptoms. These results suggest that DFPP is a beneficial therapy for neurological diseases who had no effect with drug therapy, however, serum concentrations of the immunologic markers were not necessarily correlated to the severity.

Adolescent↗
PubMed1991

Assortment of posthepatectomy hyperbilirubinemia by the occurring time with reference to indication of plasma exchange.

This study was undertaken to assort the group of posthepatectomy hyperbilirubinemia by occurring time for helping elucidate its indication of plasma exchange (PE). PE was carried out for 14 cases among 198 hepatectomized patients. The 14 cases were classified for 3 groups due to the period between operation and PE. 1: Early type (less than 2 weeks), 2:Intermediate type (2 less than-less than 8 weeks), 3: Late type (greater than 8 weeks). The results were as follows. Number (liver cirrhosis (LC)) [table: see text]. The effect was expected for the early groups since PE would remove overload against the regenerating residual liver. However, there were no survival cases among the early group or LC group. These results suggest that PE may be effective for the slowly increasing hyperbilirubinemia in not cirrhotic patients and that the state of hyperbilirubinemia is the terminal stage for LC patients even under the particular situation such as posthepatectomy.

Hepatectomy↗
PubMed1991

Excess death of lung cancer among sarcoidosis patients.

This study is to calculate a risk of lung cancer in a cohort of 1411 sarcoidosis cases which were followed for a 3 year period from 1984 to 1987. The physicians were requested to answer the questionnaire about progress of the disease by mail. Excess death was investigated using standardized mortality ratio (SMR). The expected number of deaths was calculated from Japanese sex-age specific mortality rate in 1985, using person-year method. Death from all causes and cancers did not show any excess. SMR being 0.98 and 0.97 respectively. The SMR of lung cancer was 3.26 (male: 5.56, female: 3.03), being statistically significant. The SMR of lung infection was 4.2, with statistical significance. The SMR of other main causes of death in Japan i.e., cerebrovascular accident, ischemic heart diseases and heart failure was less than 0.88. It is probably that sarcoidosis is a risk factor of lung cancer. The SMR of leukemia and uterine cancer was 5.88 and 8.70, respectively, though the observed number of leukemia was too small to conclude how high the cancer risk is among sarcoidosis patients. Gastric cancer, hepatic cancer and colon cancers were not observed.

Adult↗
PubMed1991

[Cigarette smoking and mortality among Japanese males in a prospective cohort study].

The relationship between smoking and disease was studied in a prospective cohort study among a Japanese male working population. The relative risk of cigarette smoking was positively associated with mortality for all diseases and major neoplasms. In current smokers consuming 25 to 34 cigarettes per day, relative risk for all diseases, major neoplasms, and lung cancer compared to nonsmokers was 1.38, 2.04, 2.36, respectively. These data suggest that there is a positive relation between smoking and disease mortality in this male working population. As for ex-smokers, estimated relative risk for all neoplasms was between that of current smokers and nonsmokers.

Adult↗