Picornaviral 3C cysteine proteinases have a fold similar to chymotrypsin-like serine proteinases

Nature ◽  
1994 ◽  
Vol 369 (6475) ◽  
pp. 72-76 ◽  
Author(s):  
Marc Allaire ◽  
Maia M. Chernaia ◽  
Bruce A. Malcolm ◽  
Michael N. G. James
Keyword(s):  
Serine Proteinases ◽  
Cysteine Proteinases

scholarly journals Mechanism of the reaction of papain with substrate-derived diazomethyl ketones. Implications for the difference in site specificity of halomethyl ketones for serine proteinases and cysteine proteinases and for stereoelectronic requirements in the papain catalytic mechanism

1978 ◽  
Vol 175 (2) ◽  
pp. 761-764 ◽  
Author(s):  
K Brocklehurst ◽  
J P G Malthouse
Keyword(s):  
Catalytic Mechanism ◽  
Formation Rate ◽  
Thiol Group ◽  
Site Specificity ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
Cyclic Transition ◽  
Cyclic Transition State ◽  
The Difference ◽  
Diazomethyl Ketones

The reactions of papain (EC 3.4.22.2) with substrate-derived diazomethyl ketones reported by Leary, Larsen, Watanabe & Shaw [Biochemistry (1977) 16, 5857–5861] are unusual in that (i) these reagents fail to react with low-molecular-weight thiols and (ii) the rate of reaction with the papain thiol group does not decrease to near-zero values across a pKa of 4 as the pH is decreased. Existing data are shown to suggest an interpretation involving neighbouring-group participation via transient thiohemiketal formation, rate-determining protonation by imidazolium ion and alkylation on sulphur via a three-membered cyclic transition state. Implications for (a) the difference in site-specificity exhibited by halomethyl ketones in their reactions with serine proteinases and cysteine proteinases and (b) stereoelectronic requirements in the mechanism of papain-catalysed hydrolysis are discussed. The possibility of two tetrahedral intermediates between adsorptive complex and acyl-enzyme is indicated.

scholarly journals Synthesis and properties of peptidyl derivatives of arginylfluoromethanes

1988 ◽  
Vol 256 (2) ◽  
pp. 481-486 ◽  
Author(s):  
H Angliker ◽  
P Wikström ◽  
P Rauber ◽  
S Stone ◽  
E Shaw
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Active Site ◽  
Relative Effectiveness ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
Peptide Derivatives ◽  
Guanidino Group ◽  
Derivatives Of

Two peptide derivatives of arginylfluoromethane (Arg-CH2F), namely Bz(benzoyl)-Phe-ArgCH2F and D-Phe-Pro-Arg-CH2F, have been synthesized by extension of available methods, i.e. the Dakin-West reaction [Rasnick (1985) Anal. Biochem. 149, 461-465] or synthesis of a phthaloyl-blocked C-terminal fluoromethane [Rauber, Angliker, Walker & Shaw (1986) Biochem. J. 239, 633-640; Angliker, Wikström, Rauber & Shaw (1987) Biochem. J. 241, 871-875] with subsequent elongation. The guanidino group of arginine was protected as the bis-Cbz (benzyloxycarbonyl) derivative. The products were examined as active-site-directed inhibitors of some trypsin-related serine proteinases as well as a pair of cysteine proteinases. The results extend previous observations that the rate of alkylation of serine proteinases by fluoromethanes may be considerably slower than by chloromethanes. As expected, the amino acid sequence of the inhibitors influenced their relative effectiveness. Thus the rate of inactivation of a number of trypsin-like proteinases by D-Phe-Pro-Arg-CH2F varied by more than two orders of magnitude.

scholarly journals The synthesis and properties of peptidylmethylsulphonium salts with two cationic residues as potential inhibitors of prohormone processing

1988 ◽  
Vol 256 (3) ◽  
pp. 989-994 ◽  
Author(s):  
A Zumbrunn ◽  
S Stone ◽  
E Shaw
Keyword(s):  
Cathepsin B ◽  
Proteinase Inhibitors ◽  
The Other ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
C Terminus ◽  
Prohormone Processing ◽  
Affinity Labelling ◽  
Potential Inhibitors ◽  
Cationic Residues

Peptidylmethylsulphonium salts incorporating consecutive basic residues at the C-terminus of the peptidyl portion such as -Arg-Arg-, -Arg-Lys-, -Lys-Lys- and -Lys-Arg- were synthesized and examined as proteinase inhibitors. Serine proteinases with a specificity directed towards hydrolysis at cationic residues were found to be unaffected by these derivatives. On the other hand, cysteine proteinases, cathepsin B and, in particular, clostripain were readily inactivated by affinity labelling. The reagents thus are of promise for the study of prohormone processing promoted by cysteine proteinases.

scholarly journals Inactivation of papain by antithrombin due to autolytic digestion: a model of serpin inactivation of cysteine proteinases

1998 ◽  
Vol 335 (3) ◽  
pp. 701-709 ◽  
Author(s):  
Ingemar BJÖRK ◽  
Kerstin NORDLING ◽  
Elke RAUB-SEGALL ◽  
Ulf HELLMAN ◽  
Steven T. OLSON
Keyword(s):  
Cysteine Proteinase ◽  
Cathepsin L ◽  
Serine Proteinase ◽  
Peptide Bond ◽  
Enzyme Inactivation ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
Sds Page ◽  
Reaction Proceeds ◽  
Proteinase Inhibition

Cross-class inhibition of cysteine proteinases by serpins differs from serpin inhibition of serine proteinases primarily in that no stable serpin–cysteine proteinase complex can be demonstrated. This difference in reaction mechanism was elucidated by studies of the inactivation of the cysteine proteinases, papain and cathepsin L, by the serpin antithrombin. The two proteinases were inactivated with second-order rate constants of (1.6±0.1)×103 and (8.6±0.4)×102 M-1·s-1 respectively. An antithrombin to papain inactivation stoichiometry of ∼ 3 indicated extensive cleavage of the inhibitor concurrent with enzyme inactivation, a behaviour verified by SDS/PAGE. N-terminal sequence analyses showed cleavage predominantly at the P2–P1 bond, but also at the P2´–P3´ bond of antithrombin. The papain band in SDS/PAGE progressively disappeared on reaction of the enzyme with increasing amounts of antithrombin, but no band representing a stable antithrombin–papain complex appeared. SDS/PAGE with 125I-labelled papain showed that the disappearance of papain was caused by cleavage of the enzyme into small fragments. These results suggest a mechanism in which papain attacks a peptide bond in the reactive-bond loop of antithrombin adjacent to that involved in serine proteinase inhibition. The reaction proceeds, similarly to that between serpins and serine proteinases, to form an inactive acyl-intermediate complex, although with the substrate pathway dominating in the papain reaction. In this complex, papain is highly susceptible to proteolysis and is degraded by still active papain, which greatly decreases the lifetime of the complex and results in liberation of fragmented, inactive enzyme. This model may have relevance also for the inactivation of physiologically or pathologically important cysteine proteinases by serpins.

scholarly journals The synthesis of peptidylfluoromethanes and their properties as inhibitors of serine proteinases and cysteine proteinases

1986 ◽  
Vol 239 (3) ◽  
pp. 633-640 ◽  
Author(s):  
P Rauber ◽  
H Angliker ◽  
B Walker ◽  
E Shaw
Keyword(s):  
Cathepsin B ◽  
Cysteine Proteinase ◽  
Bond Formation ◽  
Serine Proteinase ◽  
Covalent Bond ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
Active Centre ◽  
Covalent Bond Formation ◽  
The Difference

A synthesis of peptidylfluoromethanes is described that utilizes the conversion of phthaloyl amino acids into their fluoromethane derivatives. These can be deblocked and elongated. The inactivation of chymotrypsin by Cbz-Phe-CH2F (benzyloxycarbonylphenylalanylfluoromethane) was found to be considerably slower than that of the analogous chloromethane. The fluoromethane analogue inactivates chymotrypsin with an overall rate constant that is 2% of that observed for the inactivation of the enzyme with the chloromethane. However, the result is the same. The reagent complexes in a substrate-like manner, with Ki = 1.4 × 10(-4) M, and alkylates the active-centre histidine residue. Cbz-Phe-Phe-CH2F and Cbz-Phe-Ala-CH2F were investigated as inactivators of the cysteine proteinase cathepsin B. The difference in reactivity between fluoromethyl ketones and chloromethyl ketones is less pronounced in the case of the cysteine proteinase than for the serine proteinase. Covalent bond formation takes place in this case also, as demonstrated by the use of a radiolabelled reagent.

scholarly journals Inhibition of aspartic proteinases by α2-macroglobulin

1989 ◽  
Vol 259 (3) ◽  
pp. 905-907 ◽  
Author(s):  
D J Thomas ◽  
A D Richards ◽  
J Kay
Keyword(s):  
Cathepsin D ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
Aspartic Proteinases ◽  
Protein Substrates ◽  
Cathepsin E ◽  
Α2 Macroglobulin

The effect of alpha 2-macroglobulin, one of the major antiproteinases in the plasma of vertebrates, on the action of the aspartic proteinases chymosin, cathepsin D and cathepsin E towards peptide and protein substrates at pH 6.2 was examined. Activities towards protein substrates were blocked, thus demonstrating that alpha 2-macroglobulin can inhibit aspartic proteinases, in addition to serine proteinases, cysteine proteinases and metalloproteinases.

scholarly journals L-trans-Epoxysuccinyl-leucylamido(4-guanidino)butane (E-64) and its analogues as inhibitors of cysteine proteinases including cathepsins B, H and L

1982 ◽  
Vol 201 (1) ◽  
pp. 189-198 ◽  
Author(s):  
A J Barrett ◽  
A A Kembhavi ◽  
M A Brown ◽  
H Kirschke ◽  
C G Knight ◽  
...  
Keyword(s):  
Active Site ◽  
Cathepsin B ◽  
Cysteine Proteinase ◽  
Cathepsin L ◽  
Competitive Inhibitor ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
Leucocyte Elastase ◽  
Structural Analogues ◽  
Stoichiometric Reaction

1. L-trans-Epoxysuccinyl-leucylamido(4-guanidino)butane (E-64) at a concentration of 0.5 mM had no effect on the serine proteinases plasma kallikrein and leucocyte elastase or the metalloproteinases thermolysin and clostridial collagenase. In contrast, 10 muM-E-64 rapidly inactivated the cysteine proteinases cathepsins B, H and L and papain (t0.5 = 0.1-17.3s). The streptococcal cysteine proteinase reacted much more slowly, and there was no irreversible inactivation of clostripain. The cysteine-dependent exopeptidase dipeptidyl peptidase I was very slowly inactivated by E-64. 2. the active-site-directed nature of the interaction of cathepsin B and papain with E-64 was established by protection of the enzyme in the presence of the reversible competitive inhibitor leupeptin and by the stereospecificity for inhibition by the L as opposed to the D compound. 3. It was shown that the rapid stoichiometric reaction of the cysteine proteinases related to papain can be used to determine the operational molarity of solutions of the enzymes and thus to calibrate rate assays. 4. The apparent second-order rate constants for the inactivation of human cathepsins B and H and rat cathepsin L by a series of structural analogues of E-64 are reported, and compared with those for some other active-site-directed inhibitors of cysteine proteinases. 5. L-trans-Epoxysuccinyl-leucylamido(3-methyl)butane (Ep-475) was found to inhibit cathepsins B and L more rapidly than E-64. 6. Fumaryl-leucylamido(3-methyl)butane (Dc-11) was 100-fold less reactive than the corresponding epoxide, but was nevertheless about as effective as iodoacetate.

Classes and crossreactivity of proteinases in the excretory–secretory products of Caenorhabditis elegans

2007 ◽  
Vol 81 (1) ◽  
pp. 93-99
Author(s):  
S. Nic an Ultaigh ◽  
M.F. Ryan
Keyword(s):  
Caenorhabditis Elegans ◽  
Ph Value ◽  
Cross Reactivity ◽  
Serine Proteinases ◽  
Cysteine Proteinases ◽  
C Elegans ◽  
Antigenic Relatedness ◽  
Free Living Nematode ◽  
Secretory Products

AbstractProteinases released during the in vitro maintenance of asynchronous cultures of the free-living nematode Caenorhabditis elegans were characterized on the basis of subunit composition, fluorogenic substrate specificity, inhibitor sensitivity and pH optima. Cysteine proteinases are present in the excretory–secretory products (ESP) as indicated by the hydrolysis of cathepsin fluorogenic substrates and confirmed by immunoblotting. Serine proteinases were predominant as indicated by substrate gel analysis and inhibitor studies. The presence of metallo-proteinases was also indicated by inhibitor studies. The optimal pH value for cysteine proteinases was 5.5, while serine proteinases were optimal at pH 8.0. As a control, cultures of Escherichia coli, the diet of C. elegans, were extracted separately and gave no evidence of overlap with C. elegans ESP. Cross reactivity between the ESP of C. elegans and antibodies raised against the ESP of the equine parasite Strongylus vulgaris indicated antigenic relatedness of a proteic epitope. This is the first study to characterize the ESP of C. elegans and to display its relatedness with that of S. vulgaris.

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