Search PubMed⌕ Search

Biomedical subjects

S R Anderson

Publications and source records attributed to S R Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1984

Peptide binding by calmodulin and its proteolytic fragments and by troponin C.

Calmodulin and troponin C exhibit calcium-dependent binding of 1 mol/mol of dynorphin. The dissociation constants of the complexes, determined in 0.20 N KC1-1.0 mM CaCI2, pH 7.3, are 0.6 microM for calmodulin, 2.4 microM for rabbit fast skeletal muscle troponin C, and 9 microM for bovine heart troponin C. Experiments with deletion peptides of dynorphin show that peptide chain length and especially charge affect the binding of the peptides by calmodulin. Dynorphin, but not mastoparan or melittin, inhibits adenosinetriphosphatase activity in a reconstituted rabbit skeletal muscle actomyosin assay. The inhibition is partially reversed by the addition of calmodulin or troponin C in the presence of calcium. Calmodulin also exhibits calcium-dependent binding of a synthetic peptide corresponding to positions 104-115 of rabbit fast skeletal muscle troponin I. Mastoparan is a tetradecapeptide from the vespid wasp having exceptional affinity for calmodulin, with Kd approximately 0.3 nM [Malencik, D.A., & Anderson, S.R. (1983) Biochem. Biophys. Res. Commun. 114, 50]. The addition of 1 mol/mol of mastoparan to the complex of calmodulin with dynorphin results in complete dissociation of dynorphin. Similar titrations of the skeletal muscle troponin C-dynorphin complex produce a gradual dissociation consistent with a dissociation constant of 0.2 microM for the troponin C-mastoparan complex. Fluorescence anisotropy measurements using the intrinsic tryptophan fluorescence of mastoparan X show strongly calcium-dependent binding by proteolytic fragments of calmodulin. binding by proteolytic fragments of calmodulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1984

Improving the record-keeping performance of direct service personnel.

Record review procedures and contingent performance feedback were used to monitor and improve the record-keeping performance of human service staff in a behavioral residential treatment setting. A multiple baseline design was employed across three groups of B.A.-level human service personnel. The study consisted of five conditions: (1) Baseline 1; (2) Written Instructions (memoranda); (3) Written Performance Feedback; (4) Verbal Performance Feedback; and (5) Baseline 2 (return to the Baseline 1 condition). Dependent measures included highly reliable ratings by independent observers of the (1) essential documents present in case records, (2) documents approximately located/organized in case records, and (3) an overall rating of documents present, correctly organized, signed and dated, and not duplicated in the records. Results indicated that the procedures most frequently used to provide feedback to human services personnel--meetings, policy and procedure manuals, and/or written memoranda--were not as effective as verbal feedback sessions in prompting staff participation in case record maintenance. Findings were interpreted to suggest that, with adequate training, supervision, and performance appraisal, direct service personnel in residential treatment settings can effectively manage clients' case records and become more involved in, and committed to, accountability and quality control.

Employee Performance Appraisal↗
PubMed1983

High affinity binding of the mastoparans by calmodulin.

Calmodulin exhibits high affinity, calcium-dependent binding of the mastoparans--a group of cytoactive tetradecapeptides. The dissociation constants for the peptide-calmodulin complexes determined in 0.20 N KCl, 1.0 mM CaCl2, pH 7.3 are approximately 0.3 nM for mastoparan, approximately 0.9 nM for mastoparan X, and approximately 3.5 nM for Polistes mastoparan. The dissociation constant for the mastoparan-calmodulin complex is the smallest known for any calmodulin binding protein or peptide, suggesting that some type of peptide-calmodulin interaction could be physiologically significant.

Animals↗
PubMed1983

Characterization of a fluorescent substrate for the adenosine 3',5'-cyclic monophosphate-dependent protein kinase.

A synthetic tetradecapeptide derived from the phosphorylation site of the beta-subunit of phosphorylase kinase (Arg-Thr-Lys-Arg-Ser-Gly-Ser-Val-Tyr-Glu-Pro-Leu-Lys-Ile) is a highly efficient substrate for the cAMP-dependent protein kinase, exhibiting a 36% decrease in the intrinsic tyrosine fluorescence on phosphorylation. The fluorescence changes in continuous assays were monitored to demonstrate the roles of protein kinase effectors (cAMP, the type II regulatory subunit, and the 8000-Da heat-stable inhibitor) in the regulation of the enzyme and to determine Km and Vmax. The phosphorylation reaction requires 1 mol ATP/mol peptide. Amino acid analysis demonstrates the presence of phosphoserine in the phosphorylated peptide. Auxiliary experiments show that tyrosine phosphorylation can also be detected fluorometrically and distinguished from serine or threonine phosphorylation.

Amino Acid Sequence↗
PubMed1983

Binding of hormones and neuropeptides by calmodulin.

Calmodulin exhibits high-affinity, calcium-dependent binding of 1 mol/mol of the vasoactive intestinal peptide (VIP), secretin, and either the 42- or 43-residue gastric inhibitory peptide (GIP) with dissociation constants of 0.05-0.14 microM. The affinity of VIP for calmodulin approaches its affinity for the cell-surface VIP receptors. These peptides compete with both smooth muscle myosin light chain kinase and glucagon in calmodulin binding. Calculation of amino acid frequencies for eight calmodulin binding peptides (VIP, GIP, secretin, ACTH, beta-endorphin, substance P, glucagon, and dynorphin [Malencik, D. A., & Anderson, S. R. (1982) Biochemistry 21, 3480]) shows a below-average incidence of glutamyl residues, above-average incidence of glutaminyl residues, and average incidence of both aspartyl and asparaginyl residues. Predictions of structure from sequence suggest that the bound peptides contain strongly basic turns and coils in close association with regions having above-average beta-sheet potential. The temperature dependence of glucagon binding by calmodulin shows that the association is enthalpy driven.

Adrenocorticotropic Hormone↗
PubMed1982

Reconstitution of types I and II adenosine cyclic 3',5'-phosphate dependent protein kinase.

Fluorescence intensity and anisotropy measurements using the fluorescent adenosine cyclic 3',5'-phosphate (cAMP) analogue 1,N6-ethenoadenosine cyclic 3',5'-phosphate (epsilon-cAMP) are sensitive to the dissociation of epsilon-cAMP which occurs when either the type I or the type II regulatory subunit (RI or RII) of cAMP-dependent protein kinase associates with the catalytic subunit. Studies using epsilon-cAMP show that MgATP has opposite effects on the reconstitution of both types of protein kinase: MgATP strongly stabilizes the type I holoenzyme while it slightly destabilizes the type II holoenzyme. The synthetic substrate Kemptide has a small inhibitory effect on the reconstitution of both holoenzymes when tested at 10 microM concentration. The protein kinase inhibitor has a larger effect which is especially pronounced in the reassociation of the type I enzyme. The diminished relative ability of the type I regulatory subunit to compete with the protein kinase inhibitor suggests that the combined effects of the two opposing equilibria (epsilon-cAMP and catalytic subunit binding) are different for the two types of regulatory subunits. Displacement experiments show that cAMP and epsilon-cAMP bind about equally well to the type I subunit. Slow conformational changes accompanying the binding of epsilon-cAMP by both regulatory subunits are greatly accelerated with the holoenzymes, suggesting that dissociation of the holoenzymes occurs via ternary complexes. The time courses of epsilon-cAMP binding also show the heterogeneity of binding characteristics of RII. The 37 000-dalton fragment of type II subunit retains the epsilon-cAMP binding properties of the native subunit. However, only a fraction of the fragment preparation (approximately 32% estimated from sedimentation measurements) binds the catalytic subunit well, suggesting heterogeneity of cleavage.

Adenosine Triphosphate↗
PubMed1982

Binding of 5,5'-bis[8-(phenylamino)-1-naphthalenesulfonate] by the regulatory subunits of adenosine cyclic 3',5'-phosphate dependent protein kinase.

Binding to the regulatory subunits of types I and II adenosine cyclic 3',5'-phosphate (cAMP) dependent protein kinase (RI and RII, respectively) produces large distinctive increases in fluorescence and optical activity of 5,5'-bis[8-(phenylamino)-1-naphthalenesulfonate] [bis(ANS)]. Both specific and nonspecific interactions are involved. Association of the regulatory subunits with either the catalytic subunit or cAMP results in dissociation of a major portion of the bound bis(ANS) as detected by changes in fluorescence and circular dichroism. The results are consistent with the accepted cAMP binding properties of RI and RII, showing cooperativity in case of RI and two heterologous binding sites for RII. cGMP has the same overall effect on bis(ANS) binding as cAMP. However, very high concentrations are required for complete dissociation of bis(ANS) from RII, consistent with the observation that cGMP is inefficient in bringing about the dissociation of the type II holoenzyme. Magnesium binding to sites having dissociation constants of ca. 12 mM increases the interaction of bis(ANS) with both of the isolated regulatory subunits. Experiments involving the 37 000-dalton fragment of RII indicate that the limited proteolytic cleavage was heterogeneous, with only 24-39% of the resulting population interacting strongly with the catalytic subunit.

Anilino Naphthalenesulfonates↗
PubMed1982

Functional interactions between smooth muscle myosin light chain kinase and calmodulin.

Calmodulin (CaM) binding by turkey gizzard myosin light chain kinase (MLCK) causes subtle changes in the fluorescence emission and polarization excitation spectra of the enzyme. Fluorescence experiments using 9-anthroyl-choline (9AC), which competes with ATP in binding, demonstrate mutually stabilizing interactions between the CaM and ATP binding sites corresponding to delta G = -0.6 to -0.7 kcal/mol. Fluorescence titrations in the presence of 9AC or 5,5'-bis[8-(phenylamino)-1-naphthalenesulfonate] confirm the stoichiometry of 1 mol of CaM/MLCK. Phosphorylation of MLCK has no effect on either the protein fluorescence or the binding of ATP and 9AC. The dissociation constant for the MLCL-CaM complex is increased approximately 500-fold on phosphorylation. Values of Kd for the phosphorylated enzyme range from 0.5 to 1.1 microM in 0.2 N KCl, pH 7.3, 25 degrees C. We showed competition between MLCK and other CaM binding proteins and peptides by using both fluorescence and catalytic activity measurements. Competition for CaM occurs with ACTH, beta-endorphin, substance P, glucagon, poly(L-arginine), myelin basic protein, troponin I, and histone H2A. Phosphorylation of the last three proteins by the adenosine cyclic 3',5'-phosphate dependent protein kinase diminishes their ability to compete. Phosphorylation of MLCK by the protein kinase gives 0.95 +/- 0.04 and 2.2 +/- 0.4 mol of incorporated 32P in the presence and absence of CaM, respectively. These stoichiometries agree with those recently reported [Conti, M. A. & Adelstein, R. S. (1981) J. Biol. Chem. 256, 3178].

Adenosine Triphosphate↗
PubMed1982

Binding of simple peptides, hormones, and neurotransmitters by calmodulin.

We have prepared a fluorescent conjugate of porcine calmodulin with 5-(dimethylamino)-1-naphthalene-sulfonyl chloride that is highly sensitive to both calcium binding and protein binding. We have used the fluorescence of this conjugate in addition to the intrinsic peptide fluorescence to show that adrenocorticotropic hormone (ACTH), beta-endorphin, glucagon, and substance P undergo calcium-dependent binding by calmodulin, with competition for common binding sites. The dissociation constants determined in the presence of 0.85 mM CaCl2 and 0.2 N KC1, pH 7.3 at 25 degrees C, range from 1.5 muM to 3.4 muM. The alpha-melanocyte-stimulating hormone, bombesin, and somatostatin also bind, with dissociation constants between 60 muM and 90 muM. Angiotensins I and III, bradykinin, neurotensin, physalaemin, substance P octapeptide, insulin, and Leu- and Met-enkephalin show little or no binding. Sequence comparisons show that the peptides that bind calmodulin well contain regions structurally similar to the recognition sequence for the cAMP-dependent protein kinase and to the sequences surrounding phosphorylated serine residues in several calmodulin binding proteins. This result suggests that modification of calmodulin binding sites in calmodulin-dependent proteins is one of the functions of protein kinase. Calcium has a dual role in peptide binding by calmodulin. The occupation of calcium binding sites having a pK approximately 4 results in a 2-fold increase in peptide binding affinity.

Adrenocorticotropic Hormone↗
PubMed1981

Effects of halides on reduced nicotinamide adenine dinucleotide binding properties and catalytic activity of beef heart lactate dehydrogenase.

Beef heart lactate dehydrogenase has anion binding sites with selective affinities for fluoride and chloride. Fluoride competitively inhibits the catalytic activity of the enzyme and appears in a ternary enzyme-reduced nicotinamide adenine dinucleotide (NADH)-fluoride complex detectable in fluorescence and circular dichroism measurements. The presence of fluoride augments NADH binding, with a free energy of stabilization of -0.8 kcal/mol. NADH and chloride are strongly antagonistic, in fact, almost mutually exclusive or competitive, in their interaction with beef heart lactate dehydrogenase. In addition, the Hill coefficient for NADH binding undergoes a small but repeatable decline, reaching a minimum value of 0.75-0.8 at physiological NaCl concentrations. Dilution experiments showed that NADH binding in the presence of NaCl is independent of enzyme concentration, demonstrating that the chloride sensitivity is not linked to reversible dissociation of the enzyme. The NADH binding equilibria determined in NaCl, KCl, or CsCl are identical. The minimal effects of chloride on the fluorescence and circular dichroism spectra of the bound NADH suggest that it binds primarily at sites other than the one occupied by fluoride.

Animals↗
PubMed1978

Binding of ATP and of 1,N6-ethenoadensone triphosphate to rabbit muscle phosphofructokinase.

The binding of 1,N6-ethenoadenosine triphosphate (eATP) to rabbit muscle phosphofructokinase has been studied by fluorescence and circular dichroism, and compared with that of its counterpart, ATP. Muscle phosphofructokinase binds 11.3 +/- 1.2 mol of epsilonATP per tetramer with an average dissociation constant of 60 micrometer. This is in aggreement with the report of 3 ATP binding sites per phosphofructokinase protomer (Kemp & Krebs, 1967). The binding of epsilonATP is relatively homogeneous in comparison with the biphasic binding of ATP. Saturating concentrations of ATP, GTP, and ADP displace about 80% of the bound epsilonATP from the enzyme, whereas FruP2 and AMP displace only 27%. Citrate, on the other hand, enhances the affinity of phosphofructokinase for epsilonATP. The effects of the binding of ATP and epsilonATP on the conformation of enzyme have also been compared. Binding of ATP results in increases in both the lcoal rigidity and the ellipicity of the tryptophanyl side chains, whereas binding of epsilonATP causes a slight decrease in the local rigidity and has virtually no effect on the ellipticity.

Adenosine Triphosphate↗