✵ crdS gene codes the Curdlan synthase. ✵ crdA gene codes a protein which assists translocation of nascent polymer across cytoplasmic membrane. ✵ crdC gene codes a protein which assists translocation of nascent polymer across the periplasm. crdA, crdC, crdS genes occupy a contiguous 4,948-bp region in Agrobacterium sp. ATCC31749. N.B : We tried to work on these three genes. However, amplification attempts by PCR were unsuccessful for crdA and crdC genes.So, in a first time, we focused on cloning crdS gene only.