Mapping the distribution of conformational information throughout a protein sequence.
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.
Gebhard
Leopoldo G
LG
Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Sáenz Peña 180, (1876) Bernal, Buenos Aires, Argentina.
Risso
Valeria A
VA
Santos
Javier
J
Ferreyra
Raul G
RG
Noguera
Martín E
ME
Ermácora
Mario R
MR
D000595:Amino Acid Sequence; D001407:Bacillus / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D002384:Catalysis; D002850:Chromatography, Gel; D002942:Circular Dichroism; D015870:Gene Expression; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017384:Sequence Deletion / Q000235:genetics; D013056:Spectrophotometry, Ultraviolet; D001618:beta-Lactamases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D001618:beta-Lactamases