4DQV

Crystal structure of reductase (R) domain of non-ribosomal peptide synthetase from Mycobacterium tuberculosis

Summary for 4DQV

• Entry DOI: 10.2210/pdb4dqv/pdb
• Descriptor: PROBABLE PEPTIDE SYNTHETASE NRP (PEPTIDE SYNTHASE) (2 entities in total)
• Functional Keywords: gxxgxxg motif, rossmann fold, short chain dehydrogenase/reductase family, reductase, lipopeptide, ligase
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 1
• Total formula weight: 52725.95

Authors

Haque, A.S.,Panjikar, S.,Sankaranarayanan, R. (deposition date: 2012-02-16, release date: 2012-06-20, Last modification date: 2024-10-16)

Primary citation

Chhabra, A.,Haque, A.S.,Pal, R.K.,Goyal, A.,Rai, R.,Joshi, S.,Panjikar, S.,Pasha, S.,Sankaranarayanan, R.,Gokhale, R.S.
Nonprocessive [2 + 2]e- off-loading reductase domains from mycobacterial nonribosomal peptide synthetases.
Proc.Natl.Acad.Sci.USA, 109:5681-5686, 2012

PubMed Abstract: In mycobacteria, polyketide synthases and nonribosomal peptide synthetases (NRPSs) produce complex lipidic metabolites by using a thio-template mechanism of catalysis. In this study, we demonstrate that off-loading reductase (R) domain of mycobacterial NRPSs performs two consecutive [2 + 2]e(-) reductions to release thioester-bound lipopeptides as corresponding alcohols, using a nonprocessive mechanism of catalysis. The first crystal structure of an R domain from Mycobacterium tuberculosis NRPS provides strong support to this mechanistic model and suggests that the displacement of intermediate would be required for cofactor recycling. We show that 4e(-) reductases produce alcohols through a committed aldehyde intermediate, and the reduction of this intermediate is at least 10 times more efficient than the thioester-substrate. Structural and biochemical studies also provide evidence for the conformational changes associated with the reductive cycle. Further, we show that the large substrate-binding pocket with a hydrophobic platform accounts for the remarkable substrate promiscuity of these domains. Our studies present an elegant example of the recruitment of a canonical short-chain dehydrogenase/reductase family member as an off-loading domain in the context of assembly-line enzymology.

PubMed: 22451903
DOI: 10.1073/pnas.1118680109

Experimental method

X-RAY DIFFRACTION (2.3 Å)