Surface proteins of the gliding bacterium Cytophaga sp. strain U67 and its mutants defective in adhesion and motility.

Surface proteins of the gliding bacterium Cytophaga sp. strain U67 that make contact with glass substrata were radioiodinated, using a substratum-immobilized catalyst (Iodo-Gen). At least 15 polypeptides were iodinated, fewer than the number labeled by surface biotinylation of whole cells; these polypeptides define the set of possible candidates for the surface protein(s) that mediates gliding-associated substratum adhesion. The labeling of three adhesion-defective mutants exhibited two characteristic patterns of surface iodination which involved addition, loss, or alteration of several polypeptides of high molecular weight. An adhesion-competent revertant of mutant Adh3 and one of Adh2 exhibited the wild-type labeling pattern. Two other Adh2 revertants resembled their adhesion-defective parent. The labeling pattern of surface polypeptides of a nongliding but adhesive cell strain was similar to that of the wild type.