Gebhard LG, Risso VA, Santos J, Ferreyra RG, Noguera ME, Ermácora MR. Mapping the Distribution of Conformational Information Throughout a Protein Sequence.
J Mol Biol 2006;
358:280-8. [PMID:
16510154 DOI:
10.1016/j.jmb.2006.01.095]
[Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 01/26/2006] [Accepted: 01/27/2006] [Indexed: 12/01/2022]
Abstract
The three-dimensional structure of protein is encoded in the sequence, but many amino acid residues carry no essential conformational information, and the identity of those that are structure-determining is elusive. By circular permutation and terminal deletion, we produced and purified 25 Bacillus licheniformis beta-lactamase (ESBL) variants that lack 5-21 contiguous residues each, and collectively have 82% of the sequence and 92% of the non-local atom-atom contacts eliminated. Circular dichroism and size-exclusion chromatography showed that most of the variants form conformationally heterogeneous mixtures, but by measuring catalytic constants, we found that all populate, to a greater or lesser extent, conformations with the essential features of the native fold. This suggests that no segment of the ESBL sequence is essential to the structure as a whole, which is congruent with the notion that local information and modular organization can impart most of the tertiary fold specificity and cooperativity.
Collapse