4PZP: Substrate-free Structure Of D-alanine Carrier Protein Ligase Dlta From Bacillus Cereus

Citation:
Abstract
D-alanylation of the lipoteichoic acid on Gram-positive cell wall is dependent on dlt gene-encoded proteins DltA, DltB, DltC and DltD. The D-alanyl carrier protein ligase DltA, as a remote homolog of acyl-(coenzyme A) (CoA) synthetase, cycles through two active conformations for the catalysis of adenylation and subsequent thiolation of D-alanine (D-Ala). The crystal structure of DltA in the absence of any substrate was observed to have a noticeably more disordered pocket for ATP which would explain why DltA has relatively low affinity for ATP in the absence of any D-alanyl carrier. We have previously enabled the thiolation of D-alanine in the presence of CoA as the mimic of D-alanyl carrier protein DltC which carries a 4'-phosphopantetheine group on a serine residue. Here we show that the resulting Michaelis constants in the presence of saturating CoA for both ATP and D-alanine were reduced more than 10 fold as compared to the values obtained in the absence of CoA. The presence of CoA also made DltA ~100-fold more selective on D-alanine over L-alanine. The CoA-enhanced substrate recognition further implies that the ATP and D-alanine substrates of the adenylation reaction are incorporated when the DltA enzyme cycles through its thiolation conformation.
PDB ID: 4PZPDownload
MMDB ID: 125058
PDB Deposition Date: 2014/3/31
Updated in MMDB: 2014/11
Experimental Method:
x-ray diffraction
Resolution: 1.9  Å
Source Organism:
Similar Structures:
Biological Unit for 4PZP: monomeric; determined by author and by software (PISA)
Molecular Components in 4PZP
Label Count Molecule
Protein (1 molecule)
1
D-alanine--poly(phosphoribitol) Ligase Subunit 1(Gene symbol: BC1372)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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