Broad Analysis of Vicinal Disulfides: Occurrences, Conformations with Cis or with Trans Peptides, and Functional Roles Including Sugar Binding.
Vicinal disulfides between sequence-adjacent cysteine residues are very rare and rather startling structural features which play a variety of functional roles. Typically discussed as an isolated curiosity, they have never received a general treatment covering both cis and trans forms. Enabled by the growing database of high-resolution structures, required deposition of diffraction data, and improved methods for discriminating reliable from dubious cases, we identify and describe distinct protein families with reliably genuine examples of cis or trans vicinal disulfides and discuss their conformations, conservation, and functions. No cis-trans interconversions and only one case of catalytic redox function are seen. Some vicinal disulfides are essential to large, functionally coupled motions, whereas most form the centers of tightly packed internal regions. Their most widespread biological role is providing a rigid hydrophobic contact surface under the undecorated side of a sugar or multiring ligand, contributing an important aspect of binding specificity.
Department of Biochemistry, 3711 Duke University Medical Center, Durham, NC 27710, USA. Electronic address: jsr@kinemage.biochem.duke.edu.
Jane S
JS
Richardson
Department of Biochemistry, 3711 Duke University Medical Center, Durham, NC 27710, USA.
Lizbeth L
LL
Videau
Department of Biochemistry, 3711 Duke University Medical Center, Durham, NC 27710, USA.
Christopher J
CJ
Williams
Department of Biochemistry, 3711 Duke University Medical Center, Durham, NC 27710, USA.
David C
DC
Richardson
D019295:Computational Biology; D004220:Disulfides / Q000737:chemistry* / Q000378:metabolism*; D006031:Glycosylation; D008958:Models, Molecular; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*
D004220:Disulfides; D011506:Proteins
SS bond; carbohydrate binding; cis non-proline; sequence-adjacent disulfide; structural bioinformatics