Cytophaga hutchinsonii ATCC 33406 contains a structural variant of the sulfonolipid N-acylcapnine

Gliding bacteria of the genera Cytophaga and Flexibacter contain unusual sulfonolipids, called capnoids, in their outer membrane. The parent compound capnine has been identified as 2-amino-3-hydroxy-15-methylhexadecane-1-sulfonic acid. Structural studies on N-acylaminosulfonates purified from a cellulolytic cytophaga, Cytophaga hutchinsonii ATCC 33406, revealed a structural variant of the aminosulfonate core in addition to a unique 2-hydroxy fatty acyl group, i17:0(2-OH), in amide linkage with the core. The source of the structural variation in the aminosulfonate core of Cytophaga hutchinsonii arose from the addition of two carbons to the acyl chain and the insertion of two trans-double bonds. Thus, the aminosulfonate core purified from Cytophaga hutchinsonii was identified as 2-amino-3-hydroxy-trans,trans-17-methylocta-4,7-diene-1-sulfonic acid and assigned the trivial name capnosine. A second cellulolytic cytophaga, CyP2, also showed this structural variation, which was absent from the noncellulolytic isolate CyS1. Further structural studies on sulfonolipids isolated from other cellulolytic and noncellulolytic isolates will determine the taxonomic significance of this structural variant of capnine.