2c4i

From Proteopedia

Revision as of 16:59, 18 December 2007

CRYSTAL STRUCTURE OF ENGINEERED AVIDIN

Overview

Dual chain avidin (dcAvd) is an engineered avidin form, in which two, circularly permuted chicken avidin monomers are fused into one polypeptide, chain. DcAvd can theoretically form two different pseudotetrameric, quaternary assemblies because of symmetry at the monomer-monomer, interfaces. Here, our aim was to control the assembly of the quaternary, structure of dcAvd. We introduced the mutation I117C into one of the, circularly permuted domains of dcAvd and scanned residues along the 1-3, subunit interface of the other domain. Interestingly, V115H resulted in a, single, disulfide locked quaternary assembly of dcAvd, whereas I117H could, not guide the oligomerisation process even though it stabilised the, protein. The modified dcAvd forms were found to retain their, characteristic pseudotetrameric state both at high and low pH, and were, shown to bind D-biotin at levels comparable to that of wild-type chicken, avidin. The crystal structure of dcAvd-biotin complex at 1.95 Angstroms, resolution demonstrates the formation of the functional dcAvd, pseudotetramer at the atomic level and reveals the molecular basis for its, special properties. Altogether, our data facilitate further engineering of, the biotechnologically valuable dcAvd scaffold and gives insights into how, to guide the quaternary structure assembly of oligomeric proteins.

About this Structure

2C4I is a Single protein structure of sequence from Gallus gallus with SO4 and BTN as ligands. Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

Controlling quaternary structure assembly: subunit interface engineering and crystal structure of dual chain avidin., Hytonen VP, Horha J, Airenne TT, Niskanen EA, Helttunen KJ, Johnson MS, Salminen TA, Kulomaa MS, Nordlund HR, J Mol Biol. 2006 Jun 23;359(5):1352-63. Epub 2006 May 6. PMID:16787776

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