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IMGT reference sequences in FASTA format:

Amino acid sequences with gaps

The FASTA header contains:
IMGT accession number | gene and allele name | species | functionality | exon name | domain name | domain type | alternative splicing (if it is) | partial (if it is) 
>M13733|CD79A*01|Mus musculus|F|EX1|
MPGGLEALRALPLLLFLSYACL
>M13733|CD79A*01|Mus musculus|F|EX2|[D1]|C-LIKE|
GPGCQALRVEGGPPSLTVNL...GEEARLTCENNGRN.....PNITWWFSLQS.....NI
TWPPVPLGP........GQGTTGQLFFPEVNK..NTGACTGCQVIE.....NNILKRSCG
TYLRVR
>M13733|CD79A*01|Mus musculus|F|EX3|
NPVPRPFLDMGEGTKNRIITAEGIILLFCAVVPGTLLLFR
>M13733|CD79A*01|Mus musculus|F|EX4|
KRWQNEKFGVDMPDDYEDENLYE
>M13733|CD79A*01|Mus musculus|F|EX5|
GLNLDDCSMYEDISRGLQGTYQDVGNLHIGDAQLEKP