Phosphinic peptides, the first potent inhibitors of astacin, behave as extremely slow-binding inhibitors.
TL;DR: The phosphinic peptides may provide a rational basis for the design of drugs directed towards other members of the astacin family which, like bone morphogenetic protein 1 (BMP1), have become targets of pharmacological research.
Abstract: A series of phosphinic pseudo-peptides varying in length and composition have been designed as inhibitors of the crayfish zinc endopeptidase astacin, the prototype of the astacin family and of the metzincin superfamily of metalloproteinases. The most efficient phosphinic peptide, fluorenylmethyloxycarbonyl-Pro-Lys-PhePsi(PO2CH2)Ala-P ro-Leu-Val, binds to astacin with a Ki value of 42 nM, which is about three orders of magnitude below the corresponding values for previously used hydroxamic acid derivatives. However, the rate constants for association (kon = 96.8 M-1.s-1) and dissociation (koff = 4.1 x 10(-6) s-1) are evidence for the extremely slow binding behaviour of this compound. N-terminally or C-terminally truncated phosphinic analogues of this parent molecule are much less potent, indicating a critical role of the peptide size on the potency. In particular, omission of the N-terminal proline residue leads to a 40-fold increase in Ki which is mostly due to a 75-fold higher koff value. These findings are consistent with the previously solved crystal structure of astacin complexed with one of the phosphinic peptides, benzyloxycarbonyl-Pro-Lys-PhePsi(PO2CH2)Ala-Pro-O-methyl, Ki = 14 microM [Grams, Dive, Yiotakis, Yiallouros, Vassiliou, Zwilling, Bode and Stocker (1996) Nature Struct. Biol. 3, 671-675]. This structure also reveals that the phosphinic group binds to the active site as a transition-state analogue. The extremely slow binding behaviour of the phosphinic peptides is discussed in the light of the conformational changes involving a unique 'tyrosine switch' in the structure of astacin upon inhibitor binding. The phosphinic peptides may provide a rational basis for the design of drugs directed towards other members of the astacin family which, like bone morphogenetic protein 1 (BMP1; i.e. the procollagen C-proteinase), have become targets of pharmacological research.
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TL;DR: Special attention is paid to physiological functions of the astacin proteinases and to the influence of domain composition and posttranslational modifications on the activity and stability of these enzymes.
Abstract: The review deals with the properties of astacin family of zinc-dependent metalloproteinases. These enzymes exhibit arylamidase activity, which is not typical for metalloproteinases. Special attention is paid to physiological functions of the astacin proteinases and to the influence of domain composition and posttranslational modifications on the activity and stability of these enzymes.
15 citations
TL;DR: The chemoaffinity labeling experiments lead us to hypothesize that the inactivation of Proteinase K is because of the interference in the electronic microenvironment and disruption of the hydrogen-bonding network between the catalytic triad and other residues involved in catalysis.
14 citations
TL;DR: The slow semiquinone dissociation may not indicate significant thermodynamic stabilization of the reduced species in the Q(A) site, as the protein creates kinetic barriers for binding and releasing anionic hydroxyl quinones without greatly increasing the affinity relative to neutral quinone.
Abstract: Bacterial reaction centers (RCs) catalyze a series of electron-transfer reactions reducing a neutral quinone to a bound, anionic semiquinone. The dissociation constants and association rates of 13 tailless neutral and anionic benzo- and naphthoquinones for the QA site were measured and compared. The Kd values for these quinones range from 0.08 to 90 μM. For the eight neutral quinones, including duroquinone (DQ) and 2,3-dimethoxy-5-methyl-1,4-benzoquinone (UQ0), the quinone concentration and solvent viscosity dependence of the association rate indicate a second-order rate-determining step. The association rate constants (kon) range from 105 to 107 M-1 s-1. Association and dissociation rate constants were determined at pH values above the hydroxyl pKa for five hydroxyl naphthoquinones. These negatively charged compounds are competitive inhibitors for the QA site. While the neutral quinones reach equilibrium in milliseconds, anionic hydroxyl quinones with similar Kd values take minutes to bind or dissociate....
14 citations
Cites background from "Phosphinic peptides, the first pote..."
...In addition to binding tightly, many transitionstate analogues bind slowly, indicating that there are large barriers for binding these high-energy reaction intermediates (27-33)....
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TL;DR: Two conserved tyrosine residues, Tyr244 and Tyr456, were altered to phenylalanine and the mutant proteins characterized by determining KM and kcat for various amino acid beta-naphthylamide substrates caused an overall 25-100-fold reduction in catalytic activity for all substrates tested.
13 citations
TL;DR: The present article reports a low molecular weight aspartic protease inhibitor, API, from a newly isolated thermo-tolerant Bacillus licheniformis, purified to homogeneity as shown by rp-HPLC and SDS-PAGE.
12 citations
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TL;DR: Human complementary DNA clones corresponding to three polypeptides present in this BMP preparation have been isolated, and expression of the recombinant human proteins have been obtained, and each appears to be independently capable of inducing the formation of cartilage in vivo.
Abstract: Protein extracts derived from bone can initiate the process that begins with cartilage formation and ends in de novo bone formation. The critical components of this extract, termed bone morphogenetic protein (BMP), that direct cartilage and bone formation as well as the constitutive elements supplied by the animal during this process have long remained unclear. Amino acid sequence has been derived from a highly purified preparation of BMP from bovine bone. Now, human complementary DNA clones corresponding to three polypeptides present in this BMP preparation have been isolated, and expression of the recombinant human proteins have been obtained. Each of the three (BMP-1, BMP-2A, and BMP-3) appears to be independently capable of inducing the formation of cartilage in vivo. Two of the encoded proteins (BMP-2A and BMP-3) are new members of the TGF-beta supergene family, while the third, BMP-1, appears to be a novel regulatory molecule.
3,916 citations
1,671 citations
TL;DR: X‐ray crystal structures of two zinc endopeptidases, astacin from crayfish and adamalysin II from snake venom, reveal a strong overall topological equivalence and virtually identical extended HEXXHXXGXXH zinc‐binding segments, but in addition a methionine‐containing turn of similar conformation (the ‘Met‐turn’), which forms a hydrophobic basis for the zinc ion and the three liganding histidine residues.
725 citations
TL;DR: The corresponding four distinct families of zinc peptidases, the astacins, the matrix metalloproteinases (matrixins, collagenases), the adamalysins/reprolysins (snake venom proteinases/reproductive tract proteins), and the serralysins appear to have originated by divergent evolution from a common ancestor and form a superfamily of proteolytic enzymes for which the designation “metzincins” has been proposed.
Abstract: The three-dimensional structures of the zinc endopeptidases human neutrophil collagenase, adamalysin II from rattle snake venom, alkaline proteinase from Pseudomonas aeruginosa, and astacin from crayfish are topologically similar, with respect to a five-stranded beta-sheet and three alpha-helices arranged in typical sequential order. The four proteins exhibit the characteristic consensus motif HEXXHXXGXXH, whose three histidine residues are involved in binding of the catalytically essential zinc ion. Moreover, they all share a conserved methionine residue beneath the active site metal as part of a superimposable "Met-turn." This structural relationship is supported by a sequence alignment performed on the basis of topological equivalence showing faint but distinct sequential similarity. The alkaline proteinase is about equally distant (26% sequence identity) to both human neutrophil collagenase and astacin and a little further away from adamalysin II (17% identity). The pairs astacin/adamalysin II, astacin/human neutrophil collagenase, and adamalysin II/human neutrophil collagenase exhibit sequence identities of 16%, 14%, and 13%, respectively. Therefore, the corresponding four distinct families of zinc peptidases, the astacins, the matrix metalloproteinases (matrixins, collagenases), the adamalysins/reprolysins (snake venom proteinases/reproductive tract proteins), and the serralysins (large bacterial proteases from Serratia, Erwinia, and Pseudomonas) appear to have originated by divergent evolution from a common ancestor and form a superfamily of proteolytic enzymes for which the designation "metzincins" has been proposed. There is also a faint but significant structural relationship of the metzincins to the thermolysin-like enzymes, which share the truncated zinc-binding motif HEXXH and, moreover, similar topologies in their N-terminal domains.
662 citations
TL;DR: This demonstration of enzymatic activity for a BMP-1/TLD-like protein links an enzyme involved in matrix deposition to genes involved in pattern formation in vertebrate extracellular matrix.
Abstract: Bone morphogenetic proteins (BMPs) are bone-derived factors capable of inducing ectopic bone formation. Unlike other BMPs, BMP-1 is not like transforming growth factor-β (TGF-β), but it is the prototype of a family of putative proteases implicated in pattern formation during development in diverse organisms. Although some members of this group, such as Drosophila tolloid (TLD), are postulated to activate TGF-β-like proteins, actual substrates are unknown. Procollagen C-proteinase (PCP) cleaves the COOH-propeptides of procollagens I, II, and III to yield the major fibrous components of vertebrate extracellular matrix. Here it is shown that BMP-1 and PCP are identical. This demonstration of enzymatic activity for a BMP-1/TLD-like protein links an enzyme involved in matrix deposition to genes involved in pattern formation.
518 citations