Crystal Structure of a five site mutated Cyanovirin-N

Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.167 

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A Monovalent Mutant of Cyanovirin-N Provides Insight into the Role of Multiple Interactions with gp120 for Antiviral Activity.

Fromme, R.Katiliene, Z.Giomarelli, B.Bogani, F.Mahon, J.M.Mori, T.Fromme, P.Ghirlanda, G.

(2007) Biochemistry 46: 9199-9207

  • DOI: https://doi.org/10.1021/bi700666m
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Cyanovirin-N (CV-N) is a 101 amino acid cyanobacterial lectin with potent antiviral activity against HIV, mediated by high-affinity binding to branched N-linked oligomannosides on the viral surface envelope protein gp120. The protein contains two carbohydrate-binding domains, A and B, each of which binds short oligomannosides independently in vitro. The interaction to gp120 could involve either a single domain or both domains simultaneously; it is not clear which mode would elicit the antiviral activity. The model is complicated by the formation of a domain-swapped dimer form, in which part of each domain is exchanged between two monomers, which contains four functional carbohydrate-binding domains. To clarify whether multivalent interactions with gp120 are necessary for the antiviral activity, we engineered a novel mutant, P51G-m4-CVN, in which the binding site on domain A has been knocked out; in addition, a [P51G] mutation prevents the formation of domain-swapped dimers under physiological conditions. Here, we present the crystal structures at 1.8 A of the free and of the dimannose-bound forms of P51G-m4-CVN, revealing a monomeric structure in which only domain B is bound to dimannose. P51G-m4-CVN binds gp120 with an affinity almost 2 orders of magnitude lower than wt CV-N and is completely inactive against HIV. The tight binding to gp120 is recovered in the domain-swapped version of P51G-m4-CVN, prepared under extreme conditions. Our findings show that the presence of at least two oligomannoside-binding sites, either by the presence of intact domains A and B or by formation of domain-swapped dimers, is essential for activity.

  • Organizational Affiliation

    Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
109Nostoc ellipsosporumMutation(s): 5 
Gene Names: Cyanovirin-N
Find proteins for P81180 (Nostoc ellipsosporum)
Explore P81180 
Go to UniProtKB:  P81180
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP81180
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.167 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.457α = 90
b = 38.143β = 99.98
c = 56.039γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-31
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-20
    Changes: Database references
  • Version 1.3: 2023-08-30
    Changes: Data collection, Refinement description