The aglycone of sulfogalactolipids can alter the sulfate ester substitution position required for hsc70 recognition

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作者：

D Mamelak，M Mylvaganam，E Tanahashi，H Ito，C Lingwood

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摘要：

Hsp70 binding to sulfogalactolipids (SGLs) has been probed using a series of synthetic positional sulfated or phosphorylated glycolipid analogues containing either a long-chain bisalkyl hydrocarbon2-(tetradecyl)hexadecane or C 18 ceramide backbone. Recombinant hsc70 bound ceramide-based glycoconjugates having either 3′- or 4′-sulfogalactose but only the 4′-sulfogalactose positional isomer conjugated to the long-chain branched alkane. The 3′,4′-disulfate was poorly recognized, and tri-, and tetra-sulfated or phosphorylated galactolipids were not bound. These results highlight the importance of the aglycone and the position rather than the number of sulfate esters within the galactose ring. A 3′-SGL-based soluble inhibitor, in which the acyl chain of ceramide was replaced with an adamantyl group, inhibited binding of hsc70 to both 3′- and 4′-SGL species with and IC 50 of 50 and 75 μM, respectively, indicating a shared sulfogalactose binding site.

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关键词：

SGC, 3′-sulfogalactosylceramide SGG, 3′-sulfogalactosylglycerolipid SGL, sulfogalactolipid Lyso-SGC, deacylated SGC GC, galactosylceramide SLIP1, sulfoglycolipid immobilized protein 1 ABTS, 2,2′-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid IPTG, isopropyl 1-thiogalactoside GAR, goat anti-rabbit hsp, heat shock protein