Insight into the substrate length restriction of M32 carboxypeptidases: Characterization of two distinct subfamilies

M32 carboxypeptidases are a distinct family of HEXXH metalloproteases whose structures exhibit a narrow substrate groove that is blocked at one end. Structural alignments with other HEXXH metalloprotease‐peptide complexes suggested an orientation in which the substrate is directed towards the back o...

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Published inProteins, structure, function, and bioinformatics Vol. 77; no. 3; pp. 647 - 657
Main Authors Lee, Marianne M., Isaza, Clara E., White, James D., Chen, Rita P.‐Y., Liang, George F.‐C., He, Hannah T.‐F., Chan, Sunney I., Chan, Michael K.
Format Journal Article
LanguageEnglish
Published Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.11.2009
Subjects
Amino Acids - chemistry
Arginine - chemistry
Bacillus subtilis - metabolism
Carboxypeptidases - chemistry
Catalytic Domain
Cloning, Molecular
crystal structure
DNA - chemistry
Kinetics
M32 carboxypeptidase
metalloprotease
Metalloproteases - chemistry
Models, Molecular
Molecular Conformation
Protein Binding
Protein Conformation
protein degradation
Protein Structure, Tertiary
Thermus thermophilus - metabolism
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Summary:M32 carboxypeptidases are a distinct family of HEXXH metalloproteases whose structures exhibit a narrow substrate groove that is blocked at one end. Structural alignments with other HEXXH metalloprotease‐peptide complexes suggested an orientation in which the substrate is directed towards the back of the groove. This led us to hypothesize, and subsequently confirm that the maximum substrate length for M32 carboxypeptidases is restricted. Structural and sequence analyses implicate a highly conserved Arg at the back of the groove as being critical for this length restriction. However, the Thermus thermophilus and Bacillus subtilis M32 members lack this conserved Arg. Herein, we present the biochemical and structural characterization of these two proteins. Our findings support the important role of the conserved Arg in maintaining the length restriction, and reveal a proline‐rich loop as an alternate blocking strategy. Based on our results, we propose that M32 carboxypeptidases from Bacilli belong to a separate subfamily. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Bibliography:Marianne M. Lee and Clara E. Isaza contributed equally to this work.
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ISSN:0887-3585
1097-0134
DOI:10.1002/prot.22478