Manage your Funding Opportunities
  

Ninian Blackburn Institute of Environmental Health

Empty picture place holder

Ninian Blackburn

Email

Manage your Funding

Scopus Publication Detail

The publication detail shows the title, authors (with indicators showing other profiled authors), information on the publishing organization, abstract and a link to the article in Scopus. This abstract is what is used to create the fingerprint of the publication.


Interdomain long-range electron transfer becomes rate-limiting in the Y216A variant of tyramine β-monooxygenase

Robert L. Osborne; Hui Zhu; Anthony T. Iavarone; Ninian J. Blackburn; Judith P. Klinman

(Profiled Author: Ninian Blackburn)

Biochemistry. 2013;52(7):1179-1191.

Abstract

The enzyme tyramine β-monooxygenase (TβM) belongs to a small eukaryotic family of physiologically important mononuclear dicopper monooxygenases. The properties of this family include noncoupled mononuclear copper centers ∼11 Å apart, with CuM performing C-H and O2 activation and CuH functioning as an electron storage site [Klinman, J. P. (2006) J. Biol. Chem. 281, 3013-3016]. A conserved tyrosine (Y216 in TβM) is positioned between the copper domains and is associated with CuH (through an interaction with a CuH-coordinating histidine). Mutations at Y216 (to W, I, and A) indicate little or no difference in electron paramagnetic resonance spectra, while X-ray absorption spectroscopy studies show only a very small decrease in distance between CuM and its Met471 ligand in reduced enzyme. High-performance liquid chromatography assays demonstrate that turnover of substrate is complete with Y216W and Y216I, whereas Y216A undergoes a secondary inactivation that is linked to oxidation of ligands at CuM. Steady-state kinetic and isotope effect measurements were investigated. The significantly elevated Km,Tyr for Y216A, together with a very large D(kcat/Km,Tyr) of ∼12, indicates a major impact on the binding of substrate at the Cu M site. The kinetic and isotopic parameters lead to estimated rate constants for C-H bond cleavage, dissociation of substrate from the Cu M site, and, in the case of Y216A, the rate of electron transfer (ET) from CuH to CuM. These studies uncover a rate-limiting ET within the solvent-filled interface and lead to a paradigm shift in our understanding of the mononuclear dicopper monooxygenases. © 2013 American Chemical Society.


PMID: 23320946     PMCID: PMC3936603    

Scientific Context

This section shows information related to the publication - computed using the fingerprint of the publication - including related publications, related experts with fingerprints representing significant amounts of overlap between their fingerprint and this publication. The red dots indicate whether those experts or terms appear within the publication, thereby showing potential and actual connections.

Related Publications

Related Topics

Appears in this Publication Appears in this Document

Related Experts

Author of this Publication Author of this Document