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Publication Abstract from PubMed

The proline-utilization pathway in Mycobacterium tuberculosis (Mtb) has recently been identified as an important factor in Mtb persistence in vivo, suggesting that this pathway could be a valuable therapeutic target against tuberculosis (TB). In Mtb, two distinct enzymes perform the conversion of proline into glutamate: the first step is the oxidation of proline into Delta(1)-pyrroline-5-carboxylic acid (P5C) by the flavoenzyme proline dehydrogenase (PruB), and the second reaction involves converting the tautomeric form of P5C (glutamate-gamma-semialdehyde) into glutamate using the NAD(+)-dependent Delta(1)-pyrroline-5-carboxylic dehydrogenase (PruA). Here, the three-dimensional structures of Mtb-PruA, determined by X-ray crystallography, in the apo state and in complex with NAD(+) are described at 2.5 and 2.1 A resolution, respectively. The structure reveals a conserved NAD(+)-binding mode, common to other related enzymes. Species-specific conformational differences in the active site, however, linked to changes in the dimer interface, suggest possibilities for selective inhibition of Mtb-PruA despite its reasonably high sequence identity to other PruA enzymes. Using recombinant PruA and PruB, the proline-utilization pathway in Mtb has also been reconstituted in vitro. Functional validation using a novel NMR approach has demonstrated that the PruA and PruB enzymes are together sufficient to convert proline to glutamate, the first such demonstration for monofunctional proline-utilization enzymes.

Characterization of the proline-utilization pathway in Mycobacterium tuberculosis through structural and functional studies.,Lagautriere T, Bashiri G, Paterson NG, Berney M, Cook GM, Baker EN Acta Crystallogr D Biol Crystallogr. 2014 Apr 1;70(Pt 4):968-80. doi:, 10.1107/S1399004713034391. Epub 2014 Mar 19. PMID:24699642^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.