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Biomedical subjects

L H Ericsson

Publications and source records attributed to L H Ericsson.

At least 19 recordsLinked to original sources

The NH2 terminus of retinal recoverin is acylated by a small family of fatty acids.

Recoverin is a recently identified Ca(2+)-binding protein that imparts Ca2+ sensitivity to vertebrate photoreceptor guanylate cyclase. In response to photo-induced depletion of intracellular cGMP and Ca2+, recoverin stimulates resynthesis of cGMP. Bovine retinal recoverin has now been analyzed by electrospray mass spectrometry (ESI-MS) for post-translational modifications that might influence its activity. Heterogeneous acylation was detected at the NH2 terminus of bovine retinal recoverin. The NH2-terminal glycine of each retinal recoverin molecule is linked to one of four different types of acyl groups. The most abundant is myristoleate (14:1), but 14:0, 14:2, and 12:0 acyl residues are also present.

Acylation

Amino acid sequence of the biotinyl subunit from transcarboxylase.

The complete amino acid sequence of the biotinyl subunit from the enzyme transcarboxylase of Propionibacterium shermanii has been determined from the structures of overlapping tryptic and cyanogen bromide peptides together with sequenator analysis on the whole subunit. The subunit contains 123 amino acid residues. Eleven of nineteen residues in the region of biotin attachment, when compared to pyruvate carboxylase from avian liver (Rylatt, D. B., Keech, D. B., and Wallace, J. C. (1977) Arch. Biochem. Biophys. 183, 113-122), were found to be in identical positions relative to biocytin. There was less homology with acetyl-CoA carboxylase from Escherichia coli (Sutton, M. R., Fall, R. R., Nervi, A. M., Alberts, A. W., Vagelos, P. R., and Bradshaw, R. A. (1977) J. Biol. Chem. 252, 3934-3940), but in all of these biotin enzymes there was an alanylmethionyl-biocytinyl-methionine sequence. The secondary structure of the biotinyl subunit has been estimated using the method of Chou and Fasman (Chou, P. Y., and Fasman, G. D. (1978) Adv. Enzymol. 47, 45-148) and considered in relationship to the role of the biotinyl subunit in the structure and function in transcarboxylase.

Acetyl-CoA Carboxylase

Comparison of amino acid sequence of bovine coagulation Factor IX (Christmas Factor) with that of other vitamin K-dependent plasma proteins.

The amino acid sequence of bovine blood coagulation Factor IX (Christmas Factor) is presented and compared with the sequences of other vitamin K-dependent plasma proteins and pancreatic trypsinogen. The 416-residue sequence of Factor IX was determined largely by automated Edman degradation of two large segments, containing 181 and 235 residues, isolated after activating Factor IX with a protease from Russell's viper venom. Subfragments of the two segments were produced by enzymatic digestion and by chemical cleavage of methionyl, tryptophyl, and asparaginyl-glycyl bonds. Comparison of the amino acid sequences of Factor IX, Factor X, and Protein C demonstrates that they are homologous throughout. Their homology with prothrombin, however, is restricted to the amino-terminal region, which is rich in gamma-carboxyglutamic acid, and the carboxyl-terminal region, which represents the catalytic domain of these proteins and corresponds to that of pancreatic serine proteases.

Amino Acid Sequence

Sequence of the amino-terminal 349 residues of rabbit muscle glycogen phosphorylase including the sites of covalent and allosteric control.

The sequence of the amino-terminal 349 residues of rabbit muscle glycogen phosphorylase (EC 2.4.1.1) has been determined. Limited proteolysis of native phosphorylase b (841 residues, subunit molecular weight 97 412) by subtilisin BPN', Streptomyces alkaline protease, or elastase yielded two large segments (light and heavy). The light segment isolated from the subtilisin digest was cleaved at methionyl bonds with cyanogen bromide to yield eight major fragments and two minor overlapping fragments. The alignment of the major fragments was obtained by analysis of the two minor fragments, of five tryptic peptides containing methionine and of one large fragment generated by cleavage of an aspartylproline bond. Analysis of two cyanogen bromide fragments (CB14 and CB17) isolated from the intact molecule identified the sites susceptible to limited proteolysis and the overlap between the light and the heavy segments. Serine-14 and tyrosine-155 were identified as the residues involved in the covalent and allosteric controls of the enzyme, respectively. Residues 108 and 142 were identified as the cysteine residues reported to be involved in the aggregation of subunits.

Allosteric Regulation

Amino acid sequence of two cyanogen bromide fragments of glycogen phosphorylase.

This communication presents the strategy and experimental details to prove the amino acid sequence of two large fragments of rabbit muscle glycogen phosphorylase generated by cleavage with cyanogen bromide. These fragments, CB18 and CB15, represent 241 of the 841 residues in the whole molecule. In addition to applying methods of automated liquid phase Edman degradation, techniques of selective immobilization and solid phase Edman degradation are used. One of the two cyanogen bromide fragments (CB15) contains two of the sites of cleavage with hydroxylamine which have proved to be important in the overall strategy of determining the complete sequence of this molecule. Together with the accompanying reports by Koide, A., et al., and Titani, K., et al. ((1978) Biochemistry 17 (first and third papers, respectively, in a series in this issue)), the present communication completes the proof of the amino acid sequence of phosphorylase and provides the basis for examining the relationship between its structure and function.

Amino Acid Sequence

Sequence of the carboxyl-terminal 492 residues of rabbit muscle glycogen phosphorylase including the pyridoxal 5'-phosphate binding site.

This communication presents the strategy and experimental details which establish the amino acid sequence of the carboxyl-terminal 492 residues (residues 350 through 841) of rabbit muscle glycogen phosphorylase (EC 2.4.1.1). The heavy segment (Hs), derived from the native enzyme by limited proteolysis with subtilisin, was cleaved with cyanogen bromide to yield 15 fragments. The amino acid sequences of 12 of these are described herein. The sequence of 3 other fragments (CB17C, CB18, and CB15) is described in accompanying reports by Koide, A., et al., and Hermann, j., et al. ((1978) Biochemistry 17 (first and second papers, respectively, in a series in this issue)). These 15 fragments were aligned by analysis of three others generated by cleavage of the heavy segment Hs at asparaginylglycine bonds with hydroxylamine and of four more generated by acid cleavage of aspartylproline bonds. Lysine-679 was identified as the binding site of the essential cofactor pyridoxal 5'-phosphate. These data, together with those reported in the accompanying papers (vide supra), establish the complete sequence of the 841 amino acid residues in glycogen phosphorylase. They provide a chemical basis on which the relationship between structure and function of the enzyme can be examined.

Amino Acid Sequence

Precursor of egg white lysozyme. Amino acid sequence of an NH2-terminal extension.

Lysozyme mRNA was translated in a reticulocyte lysate with mixtures of radioactive amino acids. The in vitro product isolated by immunoprecipitation was shown by gel electrophoresis, peptide mapping, and sequence analysis to be larger than lysozyme synthesized in vivo. An NH2-terminal extension was completely sequenced by automated Edman degradation; the phenylthiohydantoins from each cycle were separated by high pressure liquid chromatography and quantitated by scintillation spectroscopy. The NH2-terminal sequence of pre-lysozyme is: (formula: see text) where lysine is the NH2 terminus of lysozyme. Sixteen of the eighteen residues in this sequence are hydrophobic and in this regard it resembles the partial sequences recently elucidated for other secretory proteins. The NH2-terminal methionine is donated by initiator Met-tRNAfMet; thus, this sequence represents the primary translation product. This 18-amino acid sequence is cleaved from lysozyme in vivo before the lysozyme molecules are completely synthesized.

Amino Acid Sequence

Complete amino acid sequence of rabbit muscle glycogen phosphorylase.

The sequence of the 841 amino acid residues in each subunit (molecular weight 97,412) of rabbit muscle glycogen phosphorylase b (1,4-alpha-D-glucan:orthophosphate alpha-glucosyltransferase; EC 2.4.1.1) has been determined. The general strategy was based on limited proteolysis of native phosphorylase b by subtilisin BPN', yielding two large segments (light and heavy) which were fragmented by cleavage at methyonyl-, asparaginyl-glycine, and aspartyl-proline bonds. Analysis of two cyanogen bromide fragments (CB14 and CB17) isolated from the intact molecule yielded the overlap between the light and heavy fragments and the remainder of the sequence. The residues involved in the covalent and allosteric control of the enzyme, and in the binding of the cofactor pyridoxal 5'-phosphate, were identified as serine-14, tyrosine-155, and lysine-679, respectively.

Amino Acid Sequence

Proteolytic activation of protein C from bovine plasma.

Protein C is a vitamin K dependent protein present in bovine plasma (Stenflo, J. (1976), J. Biol. Chem. 251, 355). It is a glycoprotein (mol wt approximately 62 000) composed of a heavy chain (mol wt 41 000) and a light chain (mol wt 21 000). The heavy chain has an amino-terminal sequence of Asp-Thr-Asn-Gln and contains nearly three-fourths of the carbohydrate. The light chain has an amino-terminal sequence of Ala-Asn-Ser-Phe. Incubation of protein C with either factor X activator from Russell's viper venom or trypsin resulted in the cleavage of an Arg-Ile bond between residues 14 and 15 of the heavy chain. Concomitant with this cleavage was the formation of a serine enzyme which was inhibited by diisopropyl phosphorofluoridate. Liberation of the tetradecapeptide decreased the molecular weight of the heavy chain from about 41 000 to 39 000 and resulted in the formation of a new amino-terminal sequence of Ile-Val-Asp-Gly in the heavy chain. No change in the molecular weight of the light chain was observed during the activation reaction. These results indicate that protein C, like the four vitamin K dependent coagulation proteins, exists in plasma in a precursor form and is converted to a serine protease by hydrolysis of a specific Arg-Ile peptide bond. The biological substrate for the enzymatic form of protein C and the physiological mechanism whereby protein C is converted to a serine enzyme are not known.

Acetylglucosamine

Mouse amyloid protein AA: Homology with nonimmunoglobulin protein of human and monkey amyloid substance.

The major protein extracted from anyloid deposits induced in mice by injection of either Candida albicans cells or sodium caseinate was found to have chromatographic and electrophoretic properties and an amino-acid compostiion characteristic of the AA class of amyloid proteins. The homology of the mouse protein with protein AA from man and monkey was established by determination of the sequence of the first 28 amino-acid residues.

Amino Acid Sequence

Amino acid sequence of dogfish trypsin.

The amino acid sequence of pancreatic trypsin from the spiny Pacific dogfish (Squalus acanthias) has been determined and compared with the sequences of bovine and porcine trypsin. Dogfish trypsin contains one less amino acid residue (222) than the other two enzymes. Two-thirds of the residues in corresponding positions in dogfish and bovine trypsin are identical and the sequences ofall three enzymes are homologous. Of the 223 amino acid residues of bovine trypsin, 77 are replaced without significant changes in function. Seven replacements, all conservative, occur in the interior of the protein; the remainder are on the surface. All residues known to be components of the active site of bovine trypsin are present in corresponding positions in dogfish trypsin. Comparison of the three enzymes suggests calcium binding sites in dogfish trypsin. A corrected sequence of bovine trypsin identifies residue 67 as Asn and residues 84-87 as Ser-Asn-Thr-Leu.

Amino Acid Sequence

The amino acid sequence of a carboxypeptidase inhibitor from potatoes.

The carboxypeptidase inhibitor from Russet Burbank potatoes (C. A. Ryan et al. (1974b), J. Biol. Chem 249, 5495) is a mixture of approximately equal amounts of two polypeptide chains containing 38 and 39 amino acid residues, respectively. The chains differ in their amino terminal sequence only, one beginning with smaller than Glu-His-Ala ... and the other with smaller than Glu-Gln-His-Ala ..... Specific cleavage procedures utilized in determining the complete amino acid sequence of the inhibitor included acid cleavage of the aspartyl-proline bond and tryptic and chymotryptic digestion. Mass spectrometry, automatic Edman degradation, and subtractive Edman degradation were employed in sequencing the resulting peptide fragments.

Amino Acid Sequence

Bovine factor X1 (Stuart factor). Primary structure of the light chain.

The amino-acid sequence of the light chain of bovine factor X1 is presented. The sequence of 112 of the 140 residues was determined automatically on fragments produced by specific cleavage of arginyl, glutamyl, tryptophanyl, and asparaginyl-glycine bonds. The remainder was determined by conventional procedures. The amino-terminal sequence of the light chain is homologous with the amino-terminal region of bovine prothrombin and, like the latter, appears to contain several residues of a recently discovered unusual amino acid, lambda-carboxy-glutamic acid. The role of this amino acid in the calcium-binding ability of factor X and prothrombin is discussed.

Amino Acid Sequence

Evidence of homologous relationship between thermolysin and neutral protease A of Bacillus subtilis.

A comparison of the partial amino-acid sequence of neutral protease A from Bacillus subtilis with the structure of thermolysin (EC 3.4.24.4) from Bacillus thermoproteolyticus reveals that these two proteins are homologous. Of 171 residues placed in neutral protease (54% of the sequence), 83 residues (49%) occur in identical positions in thermolysin, and include nine of the 13 residues previously identified as components of the active site of thermolysin. This similarity provides support for the hypothesis that the two enzymes have similar three-dimensional structures and a common mechanism of action. Since these enzymes differ markedly in their resistance to heat inactivation, a comparison of their structures may eventually provide a chemical basis for explaining the differences in their thermal stability.

Amino Acid Sequence