Nematodes structural considerations

A domain family that is considerably expanded in nematodes, relative to vertebrates, is the zona pellucida (ZP) domain (Bork and Sander, 1992). In database searches this domain was found in C. elegans cuticlin-1 (cut-1), a component of the nematode cuticle (Sebastiano et al., 1991), and 33 other C. elegans proteins (Table II). On the basis of disulfide-linked domains that accompany the ZP domain in these proteins, it is likely that they localize to the worm s extracellular matrix. Indeed, it is possible that most of these proteins are components of the worm cuticle. The cuticle structure is the multilayered elastic exoskeleton that determines the worm s body shape. Although vertebrates lack an equivalent... 

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