Proposed CRISPR/Cas systems in genome of YL15.

The genome of YL15 harbors (a) a putative type III-B and (b) a putative type I-F CRISPR/Cas system. The type III-B system has a cluster of genes for repeat-associated mysterious proteins (RAMPs, Cmr—Cmr6, with Cmr2/Cas10 as a signature protein), a putative Cas protein and a Cas6 protein which is involved in CRISPR transcript processing. The type I-F CRISPR/Cas system has genes encoding for a Cas1 protein, three csy proteins and a Cas3” protein which has only the HD domain of Cas3 protein. Both of the systems have genes coding for two hypothetical proteins (hyp) with unknown functions.