Glutamine residues in Q-loops of multidrug resistance protein MRP1 contribute to ATP binding via interaction with metal cofactor

Runying Yang, Yue Xian Hou, Chase A. Campbell, Kanagaraj Palaniyandi, Qing Zhao, Andrew J. Bordner, Xiu Bao Chang

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Structural analyses of bacterial ATP-binding-cassette transporters revealed that the glutamine residue in Q-loop plays roles in interacting with: 1) a metal cofactor to participate in ATP binding; 2) a putative catalytic water molecule to participate in ATP hydrolysis; 3) other residues to transmit the conformational changes between nucleotide-binding-domains and transmembrane-domains, in ATP-dependent solute transport. We have mutated the glutamines at 713 and 1375 to asparagine, methionine or leucine to determine the functional roles of these residues in Q-loops of MRP1. All these single mutants significantly decreased Mg • ATP binding and increased the Km (Mg • ATP) and Vmax values in Mg • ATP-dependent leukotriene-C4 transport. However, the Vmax values of the double mutants Q713N/Q1375N, Q713M/Q1375M and Q713L/Q1375L were lower than that of wtMRP1, implying that the double mutants cannot efficiently bind Mg • ATP. Interestingly, MRP1 has higher affinity for Mn • ATP than for Mg • ATP and the Mn • ATP-dependent leukotriene-C4 transport activities of Q713N/Q1375N and Q713M/Q1375M are significantly higher than that of wtMRP1. All these results suggest that: 1) the glutamine residues in Q-loops contribute to ATP-binding via interaction with a metal cofactor; 2) it is most unlikely that these glutamine residues would play crucial roles in ATP hydrolysis and in transmitting the conformational changes between nucleotide-binding-domains and transmembrane-domains.

Original languageEnglish (US)
Pages (from-to)1790-1796
Number of pages7
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1808
Issue number7
DOIs
StatePublished - Jul 1 2011

Keywords

  • ATP binding/hydrolysis
  • ATP dependent
  • Glutamine residue in Q-loop
  • K and V values
  • LTC4 transport
  • MRP1
  • Metal cofactor

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

Fingerprint Dive into the research topics of 'Glutamine residues in Q-loops of multidrug resistance protein MRP1 contribute to ATP binding via interaction with metal cofactor'. Together they form a unique fingerprint.

  • Cite this