Complex sentence: Four "cas" genes ("cas" 1 to 4) were recognized and the Cas proteins showed helicase and nuclease motifs, suggesting a role of these proteins in the dynamic structure of the CRISPR loci.
Split into simpler sentences: Four "cas" genes ("cas" 1 to 4) were recognized. The Cas proteins showed helicase and nuclease motifs, suggesting a role in the dynamic structure of the CRISPR loci.