Structure
| Resistin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | Resistin | ||||||||
| Pfam | PF06954 | ||||||||
| InterPro | IPR009714 | ||||||||
| SCOP | 1rgx | ||||||||
| SUPERFAMILY | 1rgx | ||||||||
| OPM superfamily | 449 | ||||||||
| OPM protein | 1rgx | ||||||||
|
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Crystal structures of resistin reveal an unusual composition of several subunits that are held together by non-covalent interactions that make up its structure. Each protein subunit comprises a carboxy-terminal disulfide-rich beta-sandwich "head" domain and an amino-terminal alpha-helical "tail" segment. The alpha-helical segments associate to form three-stranded coiled coils, and surface-exposed interchain disulfide linkages mediate the formation of tail-to-tail hexamers. The globular domain from resistin contains five disulfide bonds (Cys35-Cys88, Cys47-Cys87, Cys56-Cys73, Cys58-Cys75, and Cys62-Cys77). This suggests that the disulfide pattern with be conserved.
The interchain disulfide bonds of resistin and RELMß are novel in that they are highly solvent when exposed, ranging from 84.6% to 89.5%. An average solvent exposure for all disulfide bonds of 9.9%, and of 16.7% for 1,209 interchain disulfide bonds. Therefore, the most highly uncovered disulfide bonds found for intact proteins are resistin’s disulfides in high-resolution.
The crystal structure shows a multimeric assembly consisting of hexamer-forming disulfide bonds. A Cys6Ser resistin mutant was substantially more potent at the low concentration and had a greater effect than the wild-type resistin at the high concentration. This result suggests that processing of the intertrimer disulfide bonds may reflect a mandatory step toward activation. The results also suggest that both the Cys6Ser-mutant and wild-type resistin target mainly the liver.
Read more about this topic: Resistin
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