FIG. 7.
Assembly of CotB. Previous work has shown that CotH is needed for the assembly of CotG and CotB (30, 36). The results of the present study indicate that cotB encodes a protein of about 46 kDa which is rapidly converted into a form of about 66 kDa. The results also indicate that CotH is required directly or indirectly for the stabilization of CotG, which in turn promotes the conversion of CotB-46 into the CotB-66 form, possibly via a direct interaction with CotB-46. It is not known whether CotH directly controls the assembly of CotG or whether CotG is directly involved in the recruitment of CotB-66. However, assembly of CotB-46 can occur in the absence of CotH or CotG. Where known, the location of the indicated proteins within the coa t stucture is indicated (Oc, outer coat; Ic/Oc, inner coat-outer coat interface).