PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 11966446-5 2002 beta-amino acids, with a specific side chain, can exist as the R or S isomers at either the alpha (C2) carbon or the beta (C3) carbon. beta-amino acids 0-16 complement C2 Homo sapiens 92-101