Reactive cysteine in the structural Zn(2+) site of the C1B domain from PKC. Academic Article

abstract

• Structural cysteine-rich Zn(2+) sites that stabilize protein folds are considered to be unreactive. In this article, we identified a reactive cysteine residue, Cys151, in a treble-clef zinc finger with a Cys(3)His coordination sphere. The protein in question is the C1B domain of Protein Kinase C (PKC). Mass-tagging cysteine assays of several C1B variants were employed to ascertain the site specificity of the covalent modification. The reactivity of Cys151 in C1B also manifests itself in the structural dynamics of the Zn(2+) coordination sphere where the S of Cys151 alternates between the Zn(2+)-bound thiolate and free thiol states. We used NMR-detected pH titrations, ZZ-exchange spectroscopy, and residual dipolar coupling (RDC)-driven structure refinement to characterize the two exchanging conformations of C1B that differ in zinc coordination. Our data suggest that Cys151 serves as an entry point for the reactive oxygen species that activate PKC in a process involving Zn(2+) release.

authors

• Igumenova, Tatyana

published proceedings

• Biochemistry

author list (cited authors)

• Stewart, M. D., & Igumenova, T. I.

citation count

• 15

complete list of authors

• Stewart, Mikaela D||Igumenova, Tatyana I

publication date

• September 2012

publisher

• American Chemical Society (ACS)  Publisher

published in

• Biochemistry  Journal

keywords

• Animals
• Binding Sites
• Cysteine
• Mice
• Nuclear Magnetic Resonance, Biomolecular
• Protein Kinase C-alpha
• Protein Structure, Tertiary
• Reactive Oxygen Species
• Zinc
• Zinc Fingers

PubMed Central ID

• 22913772

Digital Object Identifier (DOI)

• 10.1021/bi300750w

start page

• 7263

end page

• 7277

volume

• 51

issue

• 37

URL

• http%3A%2F%2Fdx.doi.org%2F10.1021%2Fbi300750w