3S5X

Structure of the cyanobacterial Oscillatoria Agardhii Agglutinin (OAA) in complex with a3,a6 mannopentaose

Summary for 3S5X

• Entry DOI: 10.2210/pdb3s5x/pdb
• Related: 3OBL 3S5V 3S60
• Descriptor: Lectin, alpha-D-mannopyranose-(1-3)-alpha-D-mannopyranose-(1-6)-[alpha-D-mannopyranose-(1-3)]beta-D-mannopyranose, alpha-D-mannopyranose, ... (4 entities in total)
• Functional Keywords: beta barrel like protein, anti-hiv lectin, carbohydrate, protein binding
• Biological source: Planktothrix agardhii
• Total number of polymer chains: 1
• Total formula weight: 15755.42

Authors

Koharudin, L.M.I.,Gronenborn, A.M. (deposition date: 2011-05-23, release date: 2011-06-15, Last modification date: 2023-09-13)

Primary citation

Koharudin, L.M.,Gronenborn, A.M.
Structural basis of the anti-HIV activity of the cyanobacterial Oscillatoria Agardhii agglutinin.
Structure, 19:1170-1181, 2011

PubMed Abstract: The cyanobacterial Oscillatory Agardhii agglutinin (OAA) is a recently discovered HIV-inactivating lectin that interacts with high-mannose sugars. Nuclear magnetic resonance (NMR) binding studies between OAA and α3,α6-mannopentaose (Manα(1-3)[Manα(1-3)[Manα(1-6)]Manα(1-6)]Man), the branched core unit of Man-9, revealed two binding sites at opposite ends of the protein, exhibiting essentially identical affinities. Atomic details of the specific protein-sugar contacts in the recognition loops of OAA were delineated in the high-resolution crystal structures of free and glycan-complexed protein. No major changes in the overall protein structure are induced by carbohydrate binding, with essentially identical apo- and sugar-bound conformations in binding site 1. A single peptide bond flip at W77-G78 is seen in binding site 2. Our combined NMR and crystallographic results provide structural insights into the mechanism by which OAA specifically recognizes the branched Man-9 core, distinctly different from the recognition of the D1 and D3 arms at the nonreducing end of high-mannose carbohydrates by other antiviral lectins.

PubMed: 21827952
DOI: 10.1016/j.str.2011.05.010

Experimental method

X-RAY DIFFRACTION (1.65 Å)