2LN7: Backbone 1H, 13C, and 15N Chemical Shift Assignments for the catalytic domain of B. anthracis SrtD

Bacillus anthracis forms metabolically dormant endospores that upon germination can cause lethal anthrax disease in humans. Efficient sporulation requires the activity of the SrtC sortase (BaSrtC), a cysteine transpeptidase that covalently attaches the BasH and BasI proteins to the peptidoglycan of the forespore and predivisional cell, respectively. To gain insight into the molecular basis of protein display, we used nuclear magnetic resonance to determine the structure and backbone dynamics of the catalytic domain of BaSrtC (residues Ser(56)-Lys(198)). The backbone and heavy atom coordinates of structurally ordered amino acids have coordinate precision of 0.42 +/- 0.07 and 0.82 +/- 0.05 A, respectively. BaSrtC(Delta55) adopts an eight-stranded beta-barrel fold that contains two short helices positioned on opposite sides of the protein. Surprisingly, the protein dimerizes and contains an extensive, structurally disordered surface that is positioned adjacent to the active site. The surface is formed by two loops (beta2-beta3 and beta4-H1 loops) that surround the active site histidine, suggesting that they may play a key role in associating BaSrtC with its lipid II substrate. BaSrtC anchors proteins bearing a noncanonical LPNTA sorting signal. Modeling studies suggest that the enzyme recognizes this substrate using a rigid binding pocket and reveals the presence of a conserved subsite for the signal. This first structure of a class D member of the sortase superfamily unveils class-specific features that may facilitate ongoing efforts to discover sortase inhibitors for the treatment of bacterial infections.
PDB ID: 2LN7Download
MMDB ID: 104690
PDB Deposition Date: 2011/12/19
Updated in MMDB: 2012/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 2LN7: monomeric; determined by author
Molecular Components in 2LN7
Label Count Molecule
Protein (1 molecule)
Lpxtg-site Transpeptidase Family Protein
Molecule annotation
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