scholarly journals An amino acid sequence in the active site of lipoamide dehydrogenase from pig heart

1974 ◽  
Vol 137 (3) ◽  
pp. 505-512 ◽  
Author(s):  
Joseph P. Brown ◽  
Richard N. Perham
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Active Site ◽  
Amino Acid Sequences ◽  
Disulphide Bridge ◽  
Similar Sequence ◽  
Bacterial Enzyme ◽  
Oxoglutarate Dehydrogenase ◽  
Lipoamide Dehydrogenase ◽  
Polypeptide Chains

1. The two cysteine residues forming the disulphide bridge that comprises part of the active site of lipoamide dehydrogenase from pig heart were specifically labelled with iodo[2-14C]acetic acid. 2. A tryptic peptide containing these carboxymethylcysteine residues was isolated from digests of reduced and S-carboxymethylated lipoamide dehydrogenase and its amino acid sequence of 23 residues was determined. 3. The sequence is highly homologous with a similar sequence containing the active-site disulphide bridge of lipoamide dehydrogenase derived from the 2-oxoglutarate dehydrogenase complex of Escherichia coli (Crookes strain) and it is probable that, as in the bacterial enzyme, the disulphide bridge forms an intrachain loop containing six residues. The results indicate that the bacterial and mammalian proteins have a common genetic origin. 4. Amino acid sequences containing six other unique carboxymethylcysteine residues were also partly determined. 5. The analysis of the primary structure thus far is consistent with the view that the enzyme (mol.wt. approx. 110000) is composed of two identical polypeptide chains.

scholarly journals Amino acid sequence and oligosaccharide distribution of the haemagglutinin from an early Hong Kong influenza virus variant A/Aichi/2/68 (X-31)

1981 ◽  
Vol 193 (3) ◽  
pp. 953-962 ◽  
Author(s):  
C W Ward ◽  
T A Dopheide
Keyword(s):  
Influenza Virus ◽  
Hong Kong ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Peptide Sequencing ◽  
Amino Acid Sequences ◽  
Hydrophobic Region ◽  
Virus Variant ◽  
The Individual ◽  
Polypeptide Chains

The amino acid sequence and oligosaccharide distribution for the haemagglutinin from the early Hong Kong influenza virus A/Aichi/2/68 (X-31) was investigated. The two polypeptide chains, HA1 and HA2, were fragmented by CNBr and enzymic digestion, and the amino acid sequence of each small peptide was deduced by comparing its chromatographic behaviour, electrophoretic mobility, amino acid composition and N-terminus with that of the corresponding peptide of the haemagglutinin of known structure from the influenza-virus variant A/Memphis/102/72. Those peptides in which changes were detected were sequenced fully. The complete amino acid sequence of the haemagglutinin HA1 chain (328 residues) and 188 of the 221 residues of the HA2 chain were established by this approach, and revealed only twelve differences between the amino acid sequences of variant-A/Aichi/68 and -A/Memphis/72 haemagglutinins. These occurred at positions 2, 3, 122, 144, 155, 158, 188, 207, 242 and 275 in the HA1 chain and 150 and 216 in the HA2 chain. The highly aggregated hydrophobic region (residues 180-121) near the C-terminal end of the HA2 chain was not resolved by peptide sequencing. The oligosaccharide distribution in variant-A/Aichi/68 haemagglutinin was identical with that found in that of A/Memphis/72, with sugar units attached at asparagine residues 8, 22 38, 81, 165 and 285 in the HA1 chain and 154 on the HA2 chain. The monosaccharide compositions of the individual carbohydrate units on variant-A/Aichi/68 haemagglutinin differed from those of the corresponding units in variant-A/Memphis/72 haemagglutinin, and evidence was found for heterogeneity in the oligosaccharide units attached at single glycosylation sites.

scholarly journals Characterization of a 12-Kilodalton Rhodanese Encoded byglpE of Escherichia coli and Its Interaction with Thioredoxin

2000 ◽  
Vol 182 (8) ◽  
pp. 2277-2284 ◽  
Author(s):  
W. Keith Ray ◽  
Gang Zeng ◽  
M. Benjamin Potters ◽  
Aqil M. Mansuri ◽  
Timothy J. Larson
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Active Site ◽  
Amino Acid Sequences ◽  
E Coli ◽  
Active Site Cysteine ◽  
Clusters Of Orthologous Groups ◽  
Thioredoxin 1 ◽  
First Time

ABSTRACT Rhodaneses catalyze the transfer of the sulfane sulfur from thiosulfate or thiosulfonates to thiophilic acceptors such as cyanide and dithiols. In this work, we define for the first time the gene, and hence the amino acid sequence, of a 12-kDa rhodanese fromEscherichia coli. Well-characterized rhodaneses are comprised of two structurally similar ca. 15-kDa domains. Hence, it is thought that duplication of an ancestral rhodanese gene gave rise to the genes that encode the two-domain rhodaneses. The glpEgene, a member of the sn-glycerol 3-phosphate (glp) regulon of E. coli, encodes the 12-kDa rhodanese. As for other characterized rhodaneses, kinetic analysis revealed that catalysis by purified GlpE occurs by way of an enzyme-sulfur intermediate utilizing a double-displacement mechanism requiring an active-site cysteine. TheKm s for SSO3 2− and CN− were 78 and 17 mM, respectively. The apparent molecular mass of GlpE under nondenaturing conditions was 22.5 kDa, indicating that GlpE functions as a dimer. GlpE exhibited ak cat of 230 s−1. Thioredoxin 1 from E. coli, a small multifunctional dithiol protein, served as a sulfur acceptor substrate for GlpE with an apparentKm of 34 μM when thiosulfate was near itsKm , suggesting that thioredoxin 1 or related dithiol proteins could be physiological substrates for sulfurtransferases. The overall degree of amino acid sequence identity between GlpE and the active-site domain of mammalian rhodaneses is limited (∼17%). This work is significant because it begins to reveal the variation in amino acid sequences present in the sulfurtransferases. GlpE is the first among the 41 proteins in COG0607 (rhodanese-related sulfurtransferases) of the database Clusters of Orthologous Groups of proteins (http://www.ncbi.nlm.nih.gov/COG/ ) for which sulfurtransferase activity has been confirmed.

The amino acid sequence encompassing the active-site histidine residue of lipoamide dehydrogenase from Escherichia coli labelled with a bifunctional arsenoxide

1986 ◽  
Vol 64 (6) ◽  
pp. 509-514 ◽  
Author(s):  
Charles F. B. Holmes ◽  
Kenneth J. Stevenson
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Active Site ◽  
High Performance ◽  
Thiamine Pyrophosphate ◽  
Initial Reaction ◽  
Cnbr Cleavage ◽  
Lipoamide Dehydrogenase ◽  
Active Site Histidine ◽  
Inhibited Enzyme

Pyruvate dehydrogenase multienzyme complex (PD complex) in the presence of pyruvate, thiamine pyrophosphate, coenzyme A, and Mg2+ (or NADH) was irreversibly inhibited with the radiolabelled bifunctional arsenoxide p-[(bromoacetyl)-amino]phenyl arsenoxide (BrCH214CONHPhAsO). The initial reaction of the reagent was with a reduced lipoyl group of the lipoamide acetyltransferase component to form a dithioarsinite complex. Following the normal catalytic reactions, the anchored reagent was delivered into the active site of the lipoamide dehydrogenase (E3) component where an irreversible alkylation ensued via the bromoacetamidyl moiety. Treatment with 2,3-dithiopropanol (to break dithioarsinite bonds) caused the radio-labelled reagent to reside with E3. E3 was isolated from the inhibited PD complex and CNBr cleavage of the inhibited enzyme yielded a single radiolabelled peptide that was purified on a cyanopropyl silica column using high performance liquid chromatography. The radiolabelled amino acid was identified (after acid hydrolysis) as N3-[14C]carboxymethyl histidine in agreement with earlier studies. The radiolabel was located in residue 14 of the peptide for which the sequence was determined as[Formula: see text]This sequence agrees with the amino acid sequence determined from the gene sequence of E3. The histidine alkylated in the E3 component of the PD complex by BrCH214CONHPhAsO is residue-444 and further establishes its active site role.

scholarly journals The Evolution of Vertebrate Fibrinogen

1977 ◽  
Author(s):  
Russell F. Doolittle
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Common Ancestor ◽  
Amino Acid Sequences ◽  
Polar Material ◽  
Prototype Structure ◽  
Polypeptide Chains ◽  
Fibrinogen Molecule ◽  
The Way

The fibrinogens of all vertebrates studied to date are comprised of three pairs of non-identical polypeptide chains.Moreover, in all of these cases--whether the molecule is isolated from a primitive fish or an advanced mammal--polymerization is induced by the thrombin-cata-lyzed removal of polar peptide material from the ami no-terminal segments of two of the three chains. Amino acid sequence studies on mammalian fibrinogen molecules have provided convincing support, however, for the notion that the three non-identical polypeptide chains have evolved from a common ancestor and also that the present chains have been elongated by a series of internal duplications.Thus, we are now in a position to speculate on the structure of the primordial fibrinogen molecule and how it could be gelled by a proteolytic event. The molecule must have been comprised of (two) bundles of three identical polypeptide chains, all of which must have been sensitive to the action of thrombin.Furthermore, symmetry arguments suggest that the way the three identical chains would have been bundled together is best approximated by a (disulfide-linked) three stranded rod. Given the multiple restraints on such a molecule, a reasonable scheme can be advanced for polymerization based on the removal of polar material from one end of the rod. The differences in amino acid sequences for the three chains comprising the present day fibrinogen molecules are such that the duplicative events leading to their divergence must have occurred more than 600 million years ago, or long before the origin of vertebrates. It will be of great interest if a primitive molecule can be found in some extant creature which approximates the prototype structure.

Amino acid sequence of penicillopepsin. II. Isolation and characterization of thermolytic peptides

1976 ◽  
Vol 54 (10) ◽  
pp. 885-894 ◽  
Author(s):  
Leticia Rao ◽  
Theo Hofmann
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Active Site ◽  
Amino Acid Sequences ◽  
Porcine Pepsin ◽  
Isolation And Characterization

The determination of the amino acid sequences of 70 peptides obtained from a thermoiytic digest of penicillopepsin (EC 3.4.23.7) is described. Fifty-six unique sequences ranging from 2 to 13 amino acids were compiled. Among these was a heptapeptide whose sequence is nearly identical with that of the epoxide-reactive active site peptide of porcine pepsin (EC 3.4.23.1). Considering unrecognized overlaps, a minimum of 272 and a maximum of 293 unique amino acids have been obtained. They account for about 90% of the amino acids of the enzyme.

scholarly journals The amino acid sequence around the active-site cysteine and histidine residues of stem bromelain

1970 ◽  
Vol 117 (2) ◽  
pp. 341-346 ◽  
Author(s):  
S. S. Husain ◽  
G. Lowe
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Sodium Borohydride ◽  
Active Site ◽  
Iodoacetic Acid ◽  
Amino Acid Sequences ◽  
Histidine Residues ◽  
Active Site Cysteine ◽  
Stem Bromelain ◽  
High Degree

Stem bromelain that had been irreversibly inhibited with 1,3-dibromo[2-14C]-acetone was reduced with sodium borohydride and carboxymethylated with iodoacetic acid. After digestion with trypsin and α-chymotrypsin three radioactive peptides were isolated chromatographically. The amino acid sequences around the cross-linked cysteine and histidine residues were determined and showed a high degree of homology with those around the active-site cysteine and histidine residues of papain and ficin.

scholarly journals The amino acid sequence around the active-site cysteine and histidine residues, and the buried cysteine residues in ficin

1970 ◽  
Vol 117 (2) ◽  
pp. 333-340 ◽  
Author(s):  
S. S. Husain ◽  
G. Lowe
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Active Site ◽  
Cysteine Residue ◽  
Amino Acid Sequences ◽  
Guanidinium Chloride ◽  
Histidine Residues ◽  
Active Site Cysteine ◽  
High Degree ◽  
Salt Fractionation

Ficin that had been prepared from the latex of Ficus glabrata by salt fractionation and chromatography on carboxymethylcellulose was completely and irreversibly inhibited with 1,3-dibromo[2-14C]acetone and then treated with N-(4-dimethylamino-3,5-dinitrophenyl)maleimide in 6m-guanidinium chloride. After reduction and carboxymethylation of the labelled protein, it was digested with trypsin and α-chymotrypsin. Two radioactive peptides and two coloured peptides were isolated chromatographically and their sequences determined. The radioactive peptides revealed the amino acid sequences around the active-site cysteine and histidine residues and showed a high degree of homology with the omino acid sequence around the active-site cysteine and histidine residues in papain. The coloured peptides allowed the amino acid sequence around the buried cysteine residue in ficin to be determined.

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