Gene duplication and multiplicity of collagenases in Clostridium histolyticum

Clostridium histolyticum collagenase contains a number of different active components. Previously we have shown that colH encodes a 116-kDa collagenas e (ColH) and a 98-kDa gelatinase, We purified a different 116-kDa collagena se (ColG) from the culture supernatant and sequenced its gene (colG), We al so identified four other gelatinases (105, 82, 78, and 67 kDa) and determin ed their N-terminal amino acid sequences, all of which coincided with that of either ColG or ColH. Hybridization experiments showed that each gene is present in a single copy and each gene is transcribed into a single mRNA, T hese results suggest that all the gelatinases are produced from the respect ive full-length collagenase by the proteolytic removal of C-terminal fragme nts. The substrate specificities of the enzymes suggest that colG and colH encode class I and class II enzymes, respectively. Analysis of their DNA lo cations by pulsed-field gel electrophoresis and nucleotide sequencing of th eir surrounding regions revealed that the two genes are located in differen t sites on the chromosome. C. histolyticum colG is more similar to C. perfr ingens colA than to colH in terms of domain structure. Both colG and colA h ave a homologous gene, mscL, at their 3' ends. These results suggest that g ene duplication and segment duplication have occurred in an ancestor cell c ommon to C. histolyticum and C, perfringens and that further divergence of the parent gene produced colG and colA.