4ANE

Structure of Mycobacterium Tuberculosis Nucleoside Diphosphate Kinase R80N Mutant in Complex with Citrate

(2014) Acta Crystallogr D Biol Crystallogr 70: 40

• PubMed: 24419614 Search on PubMedSearch on PubMed Central
• DOI: https://doi.org/10.1107/S2053230X13034134
• Primary Citation of Related Structures:  
  4ANE


• PubMed Abstract: 
  

  The crystal structure of the wild-type nucleoside diphosphate kinase from Mycobacterium tuberculosis at 2.6 Å resolution revealed that the intersubunit salt bridge Arg80-Asp93 contributes to the thermal stability of the hexamer (Tm = 76°C). On mutating Asp93 to Asn to break the salt bridge, the thermal stability dramatically decreased by 27.6°C. Here, on mutating Arg80 to Asn, the thermal stability also significantly decreased by 8.0°C. In the X-ray structure of the R80N mutant solved at 1.9 Å resolution the salt bridge was replaced by intersubunit hydrogen bonds that contribute to the thermal stability of the hexamer. A citrate anion from the crystallization buffer was bound at the bottom of the nucleotide-binding site via electrostatic and hydrogen-bonding interactions with six conserved residues involved in nucleotide binding. Structural analysis shows that the citrate is present at the location of the nucleotide phosphate groups.

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Organizational Affiliation: 

Institut de Biochimie et de Génétique Cellulaires, UMR 5095, CNRS, 1 Rue Camille Saint-Saëns, 33077 Bordeaux, France.