1l1i

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Revision as of 00:11, 25 November 2007

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Solution Structure of the Tenebrio molitor Antifreeze Protein

Overview

Antifreeze proteins (AFPs) protect many types of organisms from damage, caused by freezing. They do this by binding to the ice surface, which, causes inhibition of ice crystal growth. However, the molecular mechanism, of ice binding leading to growth inhibition is not well understood. In, this paper, we present the solution structure and backbone NMR relaxation, data of the antifreeze protein from the yellow mealworm beetle Tenebrio, molitor (TmAFP) to study the dynamics in the context of structure. The, full (15)N relaxation analysis was completed at two magnetic field, strengths, 500 and 600 MHz, as well as at two temperatures, 30 and 5, degrees C, to measure the dynamic changes that occur in the protein, backbone at different temperatures. TmAFP is a small, highly, disulfide-bonded, right-handed parallel beta-helix consisting of seven, tandemly repeated 12-amino acid loops. The backbone relaxation data, displays a periodic pattern, which reflects both the 12-amino acid, structural repeat and the highly anisotropic nature of the protein., Analysis of the (15)N relaxation parameters shows that TmAFP is a, well-defined, rigid structure, and the extracted parameters show that, there is similar restricted internal mobility throughout the protein, backbone at both temperatures studied. We conclude that the hydrophobic, rigid binding site may reduce the entropic penalty for the binding of the, protein to ice. The beta-helical fold of the protein provides this, rigidity, as it does not appear to be a consequence of cooling toward a, physiologically relevant temperature.

About this Structure

1L1I is a Single protein structure of sequence from Tenebrio molitor. Full crystallographic information is available from OCA.

Reference

Structure and dynamics of a beta-helical antifreeze protein., Daley ME, Spyracopoulos L, Jia Z, Davies PL, Sykes BD, Biochemistry. 2002 Apr 30;41(17):5515-25. PMID:11969412

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