The FASTA must split into each chain, while there are no requirements for number of residues per line in the FASTA. The FASTA sequences can only contain alphabet letters except J, O, U. All lowercase letters are converted into capital letters.

>A
TPDNNKTVREFNVYWNVPTFMCHKYGLRFEEVSEKYGILQNWMDKFRGEEIAILYD
PGMFPALLKDPNGNVVARNGGVPQLGNLTKHLQVFRDHLINQIPDKSFPGVGVIDF
ESWRPIFRQNWASLQPYKKLSVEVVRREHPFWDDQRVEQEAKRRFEKYGQLFMEET
LKAAKRMRPAANWGYYAYPYCYNLTPNQPSAQCEATTMQENDKMSWLFESEDVLLP
SVYLRWNLTSGERVGLVGGRVKEALRIARQMTTSRKKVLPYYWYKYQDRRDTDLSR
ADLEATLRKITDLGADGFIIWGSSDDINTKAKCLQFREYLNNELGPAVKRIALNNN
ANDRLTVDVSVDQV

>H
QVTLKESGPGILQPSQTLSLTCSFSGFSLSTSGMGVSWIRQPSGKGLEWLAHIYWD
DDKRYNPSLKSRLTISKDTSRNQVFLKITSVDTADTATYYCTLYYGSVDYWGQGTS
VTVSSAKTTPPSVYPLAPGSAAQTNSMVTLGCLVKGYFPEPVTVTWNSGSLSSGVH
TFPAVLQSDLYTLSSSVTVPSST

>L
DIQMTQSPASLSASVGETVTITCRASENIYSYLTWYQQKQGKSPQLLVYNAKTLAE
GVPSRFSGSGSGTQFSLKISSLQPEDFGNYYCQHHYGTRTFGGGTRLEIKRADAAP
TVSIFPPSSEQLTSGGASVVCFLNNFYPKDINVKWKIDGSERQNGVLNSWTDQDSK
DSTYSMSSTLTLTKDEYERHNSYTCEATHKTSTSPIVKSFNRNEC