Thr90 is a key residue of the bacteriorhodopsin proton pumping mechanism

Alex Perálvarez, Ramon Barnadas, Manuel Sabés, Enric Querol, Esteve Padrós

Research output: Contribution to journalArticleResearchpeer-review

13 Citations (Scopus)

Abstract

Mutation of Thr90 to Ala has a profound effect on bacteriorhodopsin properties. T90A shows about 20% of the proton pumping efficiency of wild type, once reconstituted into liposomes. Mutation of Thr90 influences greatly the Schiff base/Asp85 environment, as demonstrated by altered λmax of 555 nm and pKa of Asp85 (about 1.3 pH units higher than wild type). Hydroxylamine accessibility is increased in both dark and light and differential scanning calorimetry and visible spectrophotometry show decreased thermal stability. These results suggest that Thr90 has an important structural role in both the unphotolysed bacteriorhodopsin and in the proton pumping mechanism. © 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.
Original languageEnglish
Pages (from-to)399-402
JournalFEBS Letters
Volume508
DOIs
Publication statusPublished - 23 Nov 2001

Keywords

  • Bacteriorhodopsin
  • Conformational change
  • Helical kink
  • Hydrogen bonding
  • Proton pumping
  • Thermal stability

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