Zinc Ligands in an Astacin Family Metalloprotease Meprin A

2002 ◽  
Vol 383 (7-8) ◽  
pp. 1167-1173 ◽  
Author(s):  
B. A. Doll ◽  
J. P. Villa ◽  
F. T. Ishmael ◽  
J. S. Bond

Abstract A conserved tyrosine residue in the astacin family of metalloproteases is one of five ligands proposed to coordinate zinc at the active site. Sitedirected mutagenesis of the conserved Tyr (Y226) of recombinant mouse meprin α was used to test the hypothesis that this residue is essential for zinc binding and enzymatic activity. In addition, another proposed zinc binding ligand, H167, in the conserved (HEXXH) zinc binding motif of the meprin α protease domain was replaced by an alanine residue. Both mutants were expressed and secreted with the same subunit mass as wild type (90 kDa). The Y226F mutant retained the capacity to oligomerize to higher covalently and noncovalentlylinked oligomers as the wild type, whereas H167A was predominantly a monomer. The kcat/Km for Y226F against a fluorgenic bradykinin substrate analog was approximately 15% of the wild type, while the H167A mutant had no detectable activity. Both Y226F and H167A were more susceptible to extensive degradation by trypsin compared with the wildtype protein. The zinc content in the wildtype and Y226F mutant proteins were similar, one molecule of zinc per subunit. The results indicate that Y226 is not essential for zinc binding, but Y226 and H167 are essential for full enzymatic activity and stability of the metalloproteinase.

1992 ◽  
Vol 12 (3) ◽  
pp. 1087-1095
Author(s):  
M Werner ◽  
S Hermann-Le Denmat ◽  
I Treich ◽  
A Sentenac ◽  
P Thuriaux

The conserved amino-terminal region of the largest subunit of yeast RNA polymerase C is capable of binding zinc ions in vitro. By oligonucleotide-directed mutagenesis, we show that the putative zinc-binding motif CX2CX6-12CXGHXGX24-37CX2C, present in the largest subunit of all eukaryotic and archaebacterial RNA polymerases, is essential for the function of RNA polymerase C. All mutations in the invariant cysteine and histidine residues conferred a lethal phenotype. We also obtained two conditional thermosensitive mutants affecting this region. One of these produced a form of RNA polymerase C which was thermosensitive and unstable in vitro. This instability was correlated with the loss of three of the subunits which are specific to RNA polymerase C: C82, C34, and C31.


2019 ◽  
Vol 35 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Siham A. Alissa ◽  
Hanan A. Alghulikah ◽  
Zeid A. Alothman ◽  
Sameh M. Osman ◽  
Sonia Del Prete ◽  
...  

2019 ◽  
Vol 21 (23) ◽  
pp. 12173-12183 ◽  
Author(s):  
Huawei Liu ◽  
Fan Zhang ◽  
Kai Wang ◽  
Xiaowen Tang ◽  
Ruibo Wu

Class IIa histone deacetylases (HDACs) have been considered as potential targets for the treatment of several diseases.


1992 ◽  
Vol 12 (3) ◽  
pp. 1087-1095 ◽  
Author(s):  
M Werner ◽  
S Hermann-Le Denmat ◽  
I Treich ◽  
A Sentenac ◽  
P Thuriaux

The conserved amino-terminal region of the largest subunit of yeast RNA polymerase C is capable of binding zinc ions in vitro. By oligonucleotide-directed mutagenesis, we show that the putative zinc-binding motif CX2CX6-12CXGHXGX24-37CX2C, present in the largest subunit of all eukaryotic and archaebacterial RNA polymerases, is essential for the function of RNA polymerase C. All mutations in the invariant cysteine and histidine residues conferred a lethal phenotype. We also obtained two conditional thermosensitive mutants affecting this region. One of these produced a form of RNA polymerase C which was thermosensitive and unstable in vitro. This instability was correlated with the loss of three of the subunits which are specific to RNA polymerase C: C82, C34, and C31.


2001 ◽  
Vol 358 (2) ◽  
pp. 359-367 ◽  
Author(s):  
Henning B. BOLDT ◽  
Michael T. OVERGAARD ◽  
Lisbeth S. LAURSEN ◽  
Kathrin WEYER ◽  
Lars SOTTRUP-JENSEN ◽  
...  

The bioavailability of insulin-like growth factor (IGF)-I and -II is controlled by six IGF-binding proteins (IGFBPs 1–6). Bound IGF is not active, but proteolytic cleavage of the binding protein causes release of IGF. Pregnancy-associated plasma protein-A (PAPP-A) has recently been found to cleave IGFBP-4 in an IGF-dependent manner. To experimentally support the hypothesis that PAPP-A belongs to the metzincin superfamily of metalloproteinases, all containing the elongated zinc-binding motif HEXXHXXGXXH (His-482–His-492 in PAPP-A), we expressed mutants of PAPP-A in mammalian cells. Substitution of Glu-483 with Ala causes a complete loss of activity, defining this motif as part of the active site of PAPP-A. Interestingly, a mutant with Glu-483 replaced by Gln shows residual activity. Known metzincin structures contain a so-called Met-turn, whose strictly conserved Met residue is thought to interact directly with residues of the active site. By further mutagenesis we provide experimental evidence that Met-556 of PAPP-A, 63 residues from the zinc-binding motif, is located in a Met-turn of PAPP-A. Our hypothesis is also supported by secondary-structure prediction, and the ability of a 55-residue deletion mutant (d[S498-Y552]) to express and retain antigenecity. However, because PAPP-A differs in the features defining the individual established metzincin families, we suggest that PAPP-A belongs to a separate family. We also found that PAPP-A can undergo autocleavage, and that autocleaved PAPP-A is inactive. A lack of unifying elements in the sequences around the found cleavage sites of PAPP-A and a variant suggests steric regulation of substrate specificity.


Cell ◽  
1992 ◽  
Vol 71 (5) ◽  
pp. 791-801 ◽  
Author(s):  
Xing-Wang Deng ◽  
Minami Matsui ◽  
Ning Wei ◽  
Doris Wagner ◽  
Angela M. Chu ◽  
...  

2008 ◽  
Vol 412 (3) ◽  
pp. 425-433 ◽  
Author(s):  
Hua Ren ◽  
Shuo-Xing Dou ◽  
Xing-Dong Zhang ◽  
Peng-Ye Wang ◽  
Radhakrishnan Kanagaraj ◽  
...  

RecQ family helicases, functioning as caretakers of genomic integrity, contain a zinc-binding motif which is highly conserved among these helicases, but does not have a substantial structural similarity with any other known zinc-finger folds. In the present study, we show that a truncated variant of the human RECQ5β helicase comprised of the conserved helicase domain only, a splice variant named RECQ5α, possesses neither ATPase nor DNA-unwinding activities, but surprisingly displays a strong strand-annealing activity. In contrast, fragments of RECQ5β including the intact zinc-binding motif, which is located immediately downstream of the helicase domain, exhibit much reduced strand-annealing activity but are proficient in DNA unwinding. Quantitative measurements indicate that the regulatory role of the zinc-binding motif is achieved by enhancing the DNA-binding affinity of the enzyme. The novel intramolecular modulation of RECQ5β catalytic activity mediated by the zinc-binding motif may represent a universal regulation mode for all RecQ family helicases.


2000 ◽  
Vol 275 (49) ◽  
pp. 38302-38310 ◽  
Author(s):  
Ursula Jakob ◽  
Markus Eser ◽  
James C. A. Bardwell

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