relatively long gly xaa yaa n domain containing at least 35 repeats and lacking repetitive stretches of a single amino acid motif for further selection thermal stability of the collagen like domains of selected proteins were predicted using the collagen stability calculator jupiter umdnj edu collagen_calculator and sequences showing regions of very low stability were excluded protparam tool was used for evaluation of the aa content and physicochemical parameters dna amplification and cloning full length genes for the collagen like proteins were amplified using genomic dna and corresponding primers table 1 genomic dna of clostridium perfringens c perfringens sm101 was provided by hirofumi nariya kagawa university japan dna of solibacter usitatus s usitatus was a gift from cheryl r kuske los alamos national laboratory n mex dna of methylobacteria sp 4 46 m sp 4 46 was a gift from christopher marx harvard university mass dna of rhodosudomonas palustris r palustris and corynebacterium diphtheria c diphtheria were purchased from atcc amplification conditions were optimized for each pair of primers genes were cloned in pcr 2 1 topo vector and verified by dna sequencing each collagen domain cl is denoted by the bacterial source e g cl rp is the gly xaa yaa n region from r palustris the non collagenous domains are denoted as n.