Site-specific replacement of a conserved tyrosine in ribonucleotide reductase with an aniline amino acid: A mechanistic probe for a redox-active tyrosine

Michelle C.Y. Chang, Cyril S. Yee, Daniel G. Nocera, Jo Anne Stubbe

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

An aniline-based amino acid provides a powerful mechanistic probe for redox-active tyrosines, affording a general method for elucidating the sequence of proton and electron transfer events during side-chain oxidation in biological systems. Intein technology allows Y356 to be site-specifically replaced with p-aminophenylalanine (PheNH2) on the R2 subunit of the class I ribonucleotide reductase. Analysis of the pH rate profile of Y356PheNH2-R2 strongly suggests that the mechanism of long-distance intrasubunit radical transfer through position 356 proceeds with electron transfer prior to proton transfer. In addition, we propose that radical transfer through position 356 only becomes rate-limiting upon raising the reduction potential of the residue at that location and is not affected by protonation state of either the ground state or oxidized amino acid.

Original languageEnglish (US)
Pages (from-to)16702-16703
Number of pages2
JournalJournal of the American Chemical Society
Volume126
Issue number51
DOIs
StatePublished - Dec 29 2004
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

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