A Rigid Hinge Region Is Necessary for High-Affinity Binding of Dimannose to Cyanovirin and Associated Constructs

Zhen Li; Ashini Bolia; Jason D Maxwell; Andrey A Bobkov; Giovanna Ghirlanda; S Banu Ozkan; Claudio J Margulis

doi:10.1021/acs.biochem.5b00635

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A Rigid Hinge Region Is Necessary for High-Affinity Binding of Dimannose to Cyanovirin and Associated Constructs

Journal article

Peer reviewed

A Rigid Hinge Region Is Necessary for High-Affinity Binding of Dimannose to Cyanovirin and Associated Constructs

Zhen Li, Ashini Bolia, Jason D Maxwell, Andrey A Bobkov, Giovanna Ghirlanda, S Banu Ozkan and Claudio J Margulis

Biochemistry (Easton), Vol.54(46), pp.6951-6960

11/24/2015

DOI: 10.1021/acs.biochem.5b00635

PMID: 26507789

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Abstract

Mutations in the hinge region of cyanovirin-N (CVN) dictate its preferential oligomerization state. Constructs with the Pro51Gly mutation preferentially exist as monomers, whereas wild-type cyanovirin can form domain-swapped dimers under certain conditions. Because the hinge region is an integral part of the high-affinity binding site of CVN, we investigated whether this mutation affects the shape, flexibility, and binding affinity of domain B for dimannose. Our studies indicate that the capability of monomeric wild-type CVN to resist mechanical perturbations is enhanced when compared to that of constructs in which the hinge region is more flexible. Our computational results also show that enhanced flexibility leads to blocking of the binding site by allowing different rotational isomeric states of Asn53. Moreover, at higher temperatures, this observed flexibility leads to an interaction between Asn53 and Asn42, further hindering access to the binding site. On the basis of these results, we predicted that binding affinity for dimannose would be more favorable for cyanovirin constructs containing a wild-type hinge region, whereas affinity would be impaired in the case of mutants containing Pro51Gly. Experimental characterization by isothermal titration calorimetry of a set of cyanovirin mutants confirms this hypothesis. Those possessing the Pro51Gly mutation are consistently inferior binders.

Mannose-Binding Lectins - metabolism

Protein Structure, Tertiary

Mutagenesis, Site-Directed

Disaccharides - metabolism

Bacterial Proteins - chemistry

Bacterial Proteins - genetics

Models, Molecular

Mannose-Binding Lectins - chemistry

Molecular Dynamics Simulation

Carrier Proteins - genetics

Carrier Proteins - metabolism

Mannose-Binding Lectins - genetics

Nuclear Magnetic Resonance, Biomolecular

Protein Binding

Bacterial Proteins - metabolism

Carrier Proteins - chemistry

Protein Conformation

Binding Sites

Amino Acid Substitution

Details

Title: Subtitle: A Rigid Hinge Region Is Necessary for High-Affinity Binding of Dimannose to Cyanovirin and Associated Constructs
Creators: Zhen Li - University of Iowa
Ashini Bolia - Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287-1604, United States
Jason D Maxwell - Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287-1604, United States
Andrey A Bobkov - Sanford Burnham Medical Research Institute , 10901 North Torrey Pines Road, La Jolla, California 92037, United States
Giovanna Ghirlanda - Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287-1604, United States
S Banu Ozkan - Center for Biological Physics, Department of Physics, Arizona State University , Tempe, Arizona 85287, United States
Claudio J Margulis - Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States
Resource Type: Journal article
Publication Details: Biochemistry (Easton), Vol.54(46), pp.6951-6960
Publisher: United States
DOI: 10.1021/acs.biochem.5b00635
PMID: 26507789
ISSN: 0006-2960
eISSN: 1520-4995
Grant note: DOI: 10.13039/100000152, name: Division of Molecular and Cellular Biosciences, award: 1121134, 1121276
Language: English
Date published: 11/24/2015
Academic Unit: Chemistry
Record Identifier: 9983985885102771

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