2AVW: Crystal Structure Of Monoclinic Form Of Streptococcus Mac-1

Citation:
Abstract
Group A Streptococcus secretes cysteine proteases named Mac-1 and Mac-2 that mediate host immune evasion by targeting both IgG and Fc receptors. Here, we report the crystal structures of Mac-1 and its catalytically inactive C94A mutant in two different crystal forms. Despite the lack of sequence homology, Mac-1 adopts the canonical papain fold. Alanine mutations at the active site confirmed the critical residues involved in a papain-like catalytic mechanism. Mac-1 forms a symmetric dimer in both crystal forms and displays the unique dimer interface among papain superfamily members. Mutations at the dimer interface resulted in a significant reduction in IgG binding and catalysis, suggesting that the dimer contributes to both IgG specificity and enzyme cooperativity. A tunnel observed at the dimer interface constitutes a target for designing potential Mac-1-specific antimicrobial agents. The structures also offer insight into the functional difference between Mac-1 and Mac-2.
PDB ID: 2AVWDownload
MMDB ID: 37530
PDB Deposition Date: 2005/8/30
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 2AVW: dimeric; determined by author
Molecular Components in 2AVW
Label Count Molecule
Proteins (2 molecules)
2
Igg-degrading Protease
Molecule annotation
Chemicals (2 molecules)
1
2
* Click molecule labels to explore molecular sequence information.

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