title: Domain-swapped structure of a mutant of cyanovirin-N.
abstract: Cyanovirin-N (CV-N) is a potent 11 kDa HIV-inactivating protein that binds with high affinity to the HIV surface envelope protein gp120. A double mutant P51S/S52P of CV-N was engineered by swapping two critical hinge-region residues Pro51 and Ser52. This mutant has biochemical and biophysical characteristics equivalent to the wild-type CV-N and its structure resembles that of wild-type CV-N. However, the mutant shows a different orientation in the hinge region that connects two domains of the protein. The observation that this double mutant crystallizes under a wide variety of conditions challenges some of the current hypotheses on domain swapping and on the role of hinge-region proline residues in domain orientation. The current structure contributes to the understanding of domain swapping in cyanovirins, permitting rational design of domain-swapped CV-N mutants.
authors.affiliation: Macromolecular Crystallography Laboratory, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA.
authors.forename: Istvan
authors.initials: I
authors.lastname: Botos
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mori
authors.forename: Laura K
authors.initials: LK
authors.lastname: Cartner
authors.forename: Michael R
authors.initials: MR
authors.lastname: Boyd
authors.forename: Alexander
authors.initials: A
authors.lastname: Wlodawer
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005818:Genetic Engineering; D015699:HIV Envelope Protein gp120 / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008970:Molecular Weight; D009154:Mutation; D011487:Protein Conformation; D017510:Protein Folding; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D015699:HIV Envelope Protein gp120; C107733:cyanovirin N