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Asparagine-84, a regulatory allosteric site residue, helps maintain the quaternary structure of Campylobacter jejuni dihydrodipicolinate synthase.

Majdi Yazdi M, Saran S, Mrozowich T, Lehnert C, Patel TR, Sanders DAR, Palmer DRJ
J Struct Biol 209 107409 (2020)
Cited: 2 times
EuropePMC logo PMID: 31678256

Abstract

Dihydrodipicolinate synthase (DHDPS) from Campylobacter jejuni is a natively homotetrameric enzyme that catalyzes the first unique reaction of (S)-lysine biosynthesis and is feedback-regulated by lysine through binding to an allosteric site. High-resolution structures of the DHDPS-lysine complex have revealed significant insights into the binding events. One key asparagine residue, N84, makes hydrogen bonds with both the carboxyl and the α-amino group of the bound lysine. We generated two mutants, N84A and N84D, to study the effects of these changes on the allosteric site properties. However, under normal assay conditions, N84A displayed notably lower catalytic activity, and N84D showed no activity. Here we show that these mutations disrupt the quaternary structure of DHDPS in a concentration-dependent fashion, as demonstrated by size-exclusion chromatography, multi-angle light scattering, dynamic light scattering, small-angle X-ray scattering (SAXS) and high-resolution protein crystallography.

Articles citing this publication (2)

  1. Nanoscale Structure Determination of Murray Valley Encephalitis and Powassan Virus Non-Coding RNAs. Mrozowich T, Henrickson A, Demeler B, Patel TR. Viruses 12 E190 (2020)
  2. Molecular characterization of the RNA-protein complex directing -2/-1 programmed ribosomal frameshifting during arterivirus replicase expression. Patel A, Treffers EE, Meier M, Patel TR, Stetefeld J, Snijder EJ, Mark BL. J Biol Chem 295 17904-17921 (2020)


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