Manage your Funding Opportunities

Ninian Blackburn Institute of Environmental Health

Empty picture place holder

Ninian Blackburn


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.

HHM motif at the CuH-Site of peptidylglycine monooxygenase is a pH-dependent conformational switch

Chelsey D. Kline; Mary Mayfield; Ninian J. Blackburn

(Profiled Author: Ninian Blackburn)

Biochemistry. 2013;52(15):2586-2596.


Peptidylglycine monooxygenase is a copper-containing enzyme that catalyzes the amidation of neuropeptides hormones, the first step of which is the conversion of a glycine-extended pro-peptide to its α-hydroxyglcine intermediate. The enzyme contains two mononuclear Cu centers termed CuM (ligated to imidazole nitrogens of H242, H244 and the thioether S of M314) and CuH (ligated to imidazole nitrogens of H107, H108, and H172) with a Cu-Cu separation of 11 Å. During catalysis, the M site binds oxygen and substrate, and the H site donates the second electron required for hydroxylation. The WT enzyme shows maximum catalytic activity at pH 5.8 and undergoes loss of activity at lower pHs due to a protonation event with a pKA of 4.6. Low pH also causes a unique structural transition in which a new S ligand coordinates to copper with an identical pKA, manifest by a large increase in Cu-S intensity in the X- ray absorption spectroscopy. In previous work (Bauman, A. T., Broers, B. A., Kline, C. D., and Blackburn, N. J. (2011) Biochemistry 50, 10819-10828), we tentatively assigned the new Cu-S interaction to binding of M109 to the H-site (part of an HHM conserved motif common to all but one member of the family). Here we follow up on these findings via studies on the catalytic activity, pH-activity profiles, and spectroscopic (electron paramagnetic resonance, XAS, and Fourier transform infrared) properties of a number of H-site variants, including H107A, H108A, H172A, and M109I. Our results establish that M109 is indeed the coordinating ligand and confirm the prediction that the low pH structural transition with associated loss of activity is abrogated when the M109 thioether is absent. The histidine mutants show more complex behavior, but the almost complete lack of activity in all three variants coupled with only minor differences in their spectroscopic properties suggests that unique structural elements at H are critical for functionality. The data suggest a more general utility for the HHM motif as a copper- and pH-dependent conformational switch. © 2013 American Chemical Society.

PMID: 23530865     PMCID: PMC3746079    

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