Capsid protein gene sequence of feline calicivirus isolates 255 and LLK: further evidence for capsid protein configuration among feline caliciviruses.

The capsid protein gene sequences are reported for two feline calicivirus (FCV) isolates, one a highly virulent isolate associated with respiratory disease, designated 255, and an isolate associated with neuromuscular disorders, designated LLK. Both capsid protein sequences conform to a previously described hypothesis wherein FCV capsid proteins may be divided into six regions based on sequence similarity among isolates. Region A corresponds to the amino-terminal area of the protein that is theoretically cleaved to produce the functional species. With a large area of sequence identity among isolates, region B contains a potential myristilated glycine and a putative ATP/GTP binding site. Region C is a short hypervariable sequence of unknown function followed by another conserved area designated region D. The E region is an area of extensive amino acid sequence hypervariability that presumably contains the antigenic determinants of the capsid protein. Region F contains the highly conserved carboxy-terminal portion of the protein.