A monovalent mutant of cyanovirin-N provides insight into the role of multiple interactions with gp120 for antiviral activity. Export

@article{citeulike:3180057, 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.}, address = {Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA.}, author = {Fromme, R. and Katiliene, Z. and Giomarelli, B. and Bogani, F. and Mc Mahon, J. and Mori, T. and Fromme, P. and Ghirlanda, G.}, citeulike-article-id = {3180057}, citeulike-linkout-0 = {http://dx.doi.org/10.1021/bi700666m}, citeulike-linkout-1 = {http://pubs.acs.org/doi/abs/10.1021/bi700666m}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/17636873}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=17636873}, day = {14}, doi = {10.1021/bi700666m}, issn = {0006-2960}, journal = {Biochemistry}, keywords = {cyanoviron, lectin}, month = {August}, number = {32}, pages = {9199--9207}, posted-at = {2008-09-01 22:45:43}, priority = {0}, title = {A monovalent mutant of cyanovirin-N provides insight into the role of multiple interactions with gp120 for antiviral activity.}, url = {http://dx.doi.org/10.1021/bi700666m}, volume = {46}, year = {2007} }

TY - JOUR ID - citeulike:3180057 L3 - citeulike-article-id:3180057 N2 - 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. IS - 32 JF - Biochemistry SN - 0006-2960 AD - Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA. EP - 9207 TI - A monovalent mutant of cyanovirin-N provides insight into the role of multiple interactions with gp120 for antiviral activity. VL - 46 SP - 9199 KW - cyanoviron KW - lectin AU - Fromme, R AU - Katiliene, Z AU - Giomarelli, B AU - Bogani, F AU - Mc Mahon, J AU - Mori, T AU - Fromme, P AU - Ghirlanda, G PY - 2007/08/14/ UR - http://dx.doi.org/10.1021/bi700666m ER -