Crystal structure of a putative lysostaphin peptidase from Vibrio cholerae

A feeding tube model for activation of a cell-specific transcription factor during sporulation in Bacillus subtilis

“…S1), as has been previously noted (Londoñ o-Vallejo et al 1997;Smith et al 2000;Sun et al 2000). The Q proteins from Bacilli have maintained the presumed catalytic histidine residue (His202 in B. subtilis Q) as well as two of the three amino acid residues that coordinate a zinc ion (Zn 2+ ) (Asp123 and His204 in B. subtilis Q) (Gustin et al 1996;Odintsov et al 2004;Firczuk et al 2005;Ragumani et al 2008;Rawlings et al 2008). Interestingly, His202-Pro216 lie within this lysostaphin-like region and harbor the presumed catalytic histidine residue (His202) and one of the potential Zn 2+ -coordinating residues (His204).…”

Crystal Structure of the LasA Virulence Factor from Pseudomonas aeruginosa: Substrate Specificity and Mechanism of M23 Metallopeptidases

“…A number of previous proposals have suggested that one of the two conserved histidine residues (LasA His81; His120) could act as a general base to activate the hydrolytic water molecule. 39,46,65,66 However, as interaction of Zn 2+ with the substrate carbonyl carbon is also expected to be important to substrate binding and activation, 66 it is difficult to reconcile the presence of both substrate and Zn 2+ -bound water with the available crystallographic evidence for a tetrahedral Zn 2+ centre. Our structure of uncomplexed LasA now shows how incoming substrate could bind Zn 2+ (by displacing Wat2) whilst retaining a metal-bound water molecule (Wat1) that is appropriately positioned and oriented to act as the nucleophile in the hydrolytic reaction by virtue of its interaction with both conserved histidine residues.…”

“…Atom colours are as standard, except C α atoms (colour ramped from N-(red) to C-(blue) terminus). c, Active sites of (left) gp13 36 , (centre) V. cholerae M23B putative peptidase 46 (PDB accession code 2GU1) and (right) P. aeruginosa putative M23B peptidase (PDB accession code 2HSI) shown in equivalent orientations and coloured as described above. distances given are for subunit A).…”

“…2a), suggesting that changes in the conformation of loop 3 might be associated with substrate binding. DALI 52 and manual searching of the protein databank 53 identified five structures related to LasA: domain IIA of Bacillus subtilis glucose permease (whose structural relation to M23 peptidases has already been noted 44 ); 54 the LytM glycylglycine endopeptidase from Staphylococcus aureus; 44,45 two other putative M23B peptidases of unknown function from Pseudomonas aeruginosa (PDB accession number 2HSI) and Vibrio cholerae; 46 and the Cterminal domain of the gp13 protein of Bacillus subtilis bacteriophage ϕ29. 36 As the P. aeruginosa and V. cholerae structures closely resemble that of LytM (maximal RMSD of 1.38 Å), and little biochemical information is available for these proteins, our discussion is concentrated upon comparisons of LasA with the LytM and gp13 structures ( Fig.…”

“…36 A comparison of the active site of the S. aureus autolysin LytM with more distantly related D-Ala-DAla metallopeptidases, such as VanX 37 and S. albus G carboxypeptidase, 38 has led to the suggestion that M23 metallopeptidases are part of a larger metalloenzyme superfamily termed LAS enzymes, that act primarily as peptidoglycan hydrolases. 39 An increasing number of M23 metallopeptidases are undergoing experimental characterisation, [40][41][42][43] and crystal structures of some family members are now available, [44][45][46] but many aspects of these and related enzymes are poorly understood. In particular, the relationship between structure and substrate specificity for the different classes of M23 and related enzymes remains to be established and, despite a number of proposals, there is no consensus regarding a catalytic mechanism for these enzymes.…”