5huq
From Proteopedia
A tethered niacin-derived pincer complex with a nickel-carbon bond in lactate racemase
Structural highlights
FunctionLARA_LACPL Catalyzes the interconversion between the D- and L-isomers of lactate (PubMed:24710389, PubMed:26138974). May act as a rescue enzyme to ensure D-lactate production in physiological conditions where its production by the D-lactate dehydrogenase LdhD is not sufficient (PubMed:16166538). D-Lactate is absolutely required for growth of L.plantarum and is an essential component of the cell wall peptidoglycan in this species, where it is incorporated as the last residue of the muramoyl-pentadepsipeptide peptidoglycan precursor; its incorporation confers high level of vancomycin resistance (PubMed:16166538).[1] [2] [3] Publication Abstract from PubMedLactic acid racemization is involved in lactate metabolism and cell wall assembly of many microorganisms. Lactate racemase (Lar) requires nickel, but the nickel-binding site and the role of three accessory proteins required for its activation remain enigmatic. We combined mass spectrometry and x-ray crystallography to show that Lar from Lactobacillus plantarum possesses an organometallic nickel-containing prosthetic group. A nicotinic acid mononucleotide derivative is tethered to Lys(184) and forms a tridentate pincer complex that coordinates nickel through one metal-carbon and two metal-sulfur bonds, with His(200) as another ligand. Although similar complexes have been previously synthesized, there was no prior evidence for the existence of pincer cofactors in enzymes. The wide distribution of the accessory proteins without Lar suggests that it may play a role in other enzymes. METALLOPROTEINS. A tethered niacin-derived pincer complex with a nickel-carbon bond in lactate racemase.,Desguin B, Zhang T, Soumillion P, Hols P, Hu J, Hausinger RP Science. 2015 Jul 3;349(6243):66-9. doi: 10.1126/science.aab2272. PMID:26138974[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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