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

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.

1970 ◽  
Vol 117 (2) ◽  
pp. 341-346 ◽  
Author(s):  
S. S. Husain ◽  
G. Lowe

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.


1971 ◽  
Vol 123 (4) ◽  
pp. 591-600 ◽  
Author(s):  
John Bridgen

Four unique carboxymethylcysteine-containing peptides were isolated from tryptic and chymotryptic digests of trout muscle actin carboxymethylated with iodo[2-14C]acetic acid in 6m-guanidinium chloride. The amino acid sequences of these peptides were determined and showed a high degree of homology with the corresponding sequences from rabbit actin. One of the radioactive peptides was the C-terminal peptide and another sequence probably contained the cysteine residue from the N-terminal region of the protein.


2000 ◽  
Vol 182 (8) ◽  
pp. 2277-2284 ◽  
Author(s):  
W. Keith Ray ◽  
Gang Zeng ◽  
M. Benjamin Potters ◽  
Aqil M. Mansuri ◽  
Timothy J. Larson

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.


1968 ◽  
Vol 108 (5) ◽  
pp. 861-866 ◽  
Author(s):  
S. S. Husain ◽  
G. Lowe

Papain 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 the radioactive peptides were purified chromatographically. Their amino acid composition indicated that cysteine-25 and histidine-106 were cross-linked. Since cysteine-25 is known to be the active-site cysteine residue, histidine-106 must be the active-site histidine residue.


1989 ◽  
Vol 44 (7) ◽  
pp. 817-824 ◽  
Author(s):  
Aftab Ahmed ◽  
Meeno Jahan ◽  
Gerhard Braunitzer ◽  
Helmut Pechlaner

The complete amino acid sequences of the hemoglobins from the adult European polecat (Mustela putorius) are presented. The erythrocytes contain two hemoglobin components and three globin chains (α I, α II and β). The primary structure of globin chains and of the tryptic peptides determined in liquid- and gas-phase sequantors. Comparing the sequences of the globin chains of the polecat with that of human Hb-A, 17 (23.9%) substitutions were recognized in the α I, 16 (22.5%) in the α II and 14 (20.4%) in the β chain. A high degree of homology observed with other representatives of the family Mustelidae.


1971 ◽  
Vol 124 (1) ◽  
pp. 61-67 ◽  
Author(s):  
P. H. Corran ◽  
S. G. Waley

1. Calf lens α-crystallin was carboxymethylated with radioactive sodium iodoacetate to label the thiol group. 2. The protein was then digested with trypsin or alternatively fractionated in urea to obtain the acidic (A) chains, which were then digested with trypsin. Either procedure gave two radioactive peptides containing carboxymethylcysteine. 3. These two peptides were closely related: the longer form contained 28 amino acid residues, and the shorter lacked two residues at the N-terminal end of the longer form. 4. The amino acid sequence of the peptides have been determined. 5. No evidence for the presence of more than one cysteine residue/chain was found. 6. The question of the molecular weight of the chains is discussed.


1977 ◽  
Vol 163 (2) ◽  
pp. 309-316 ◽  
Author(s):  
I A Simpson ◽  
M R Hollaway ◽  
J Beard

1. The single highly reactive (class I) thiol group per 80000-mol.wt. subunit of skeletal-muscle phosphofructokinase was specifically carboxymethylated with iodo[2-14C]acetate, and after denaturation the remaining thiol groups were carboxymethylated with bromo[2-3H]acetate. After tryptic digestion and peptide ‘mapping’ it was found that the 14C radioactivity was in a spot that did not contain significant amounts of 3H radioactivity, so it is concluded that there is not a second, ‘buried’ cysteine residue within a sequence identical with that of the class-I cysteine peptide. 2. The total number of tryptic peptides as well as the number of those containing cysteine, histidine or tryptophan were inconsistent with the smallest polypeptide chain of phosphofructokinase (mol.wt. about 80000) being composed of two identical amino acid sequences. 3. The amino acid sequence of the tryptic peptide containing the class-I thiol group was shown to be Cys-Lys-Asp-Phe-Arg. This sequence is compared with part of the sequence containing the highly reactive thiol group of phosphorylase.


1974 ◽  
Vol 137 (3) ◽  
pp. 505-512 ◽  
Author(s):  
Joseph P. Brown ◽  
Richard N. Perham

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.


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