Here you are: IMGT Web resources > IMGT Repertoire (RPI) > RPI entries from gene to protein

IMGT reference sequences in FASTA format:

Nucleotide sequences without 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) 
>M37812|CD28*01|Homo sapiens|F|EX1|
atgctcaggctgctcttggctctcaacttattcccttcaattcaagtaacag
>M37813|CD28*01|Homo sapiens|F|EX2|[D]|V-LIKE|
gaaacaagattttggtgaagcagtcgcccatgcttgtagcgtacgacaatgcggtcaacc
ttagctgcaagtattcctacaatctcttctcaagggagttccgggcatcccttcacaaag
gactggatagtgctgtggaagtctgtgttgtatatgggaattactcccagcagcttcagg
tttactcaaaaacggggttcaactgtgatgggaaattgggcaatgaatcagtgacattct
acctccagaatttgtatgttaaccaaacagatatttacttctgcaaaattgaagttatgt
atcctcctccttacctagacaatgagaagagcaatggaaccattatccatgtgaaag
>M37814|CD28*01|Homo sapiens|F|EX3|
ggaaacacctttgtccaagtcccctatttcccggaccttctaagcccttttgggtgctgg
tggtggttggtggagtcctggcttgctatagcttgctagtaacagtggcctttattattt
tctgg
>M37815|CD28*01|Homo sapiens|F|EX4|
gtgaggagtaagaggagcaggctcctgcacagtgactacatgaacatgactccccgccgc
cccgggcccacccgcaagcattaccagccctatgccccaccacgcgacttcgcagcctat
cgctcc
>CD28*01|Homo sapiens|F|EX1-EX4|Splicing A|complete|
atgctcaggctgctcttggctctcaacttattcccttcaattcaagtaacaggaaacaag
attttggtgaagcagtcgcccatgcttgtagcgtacgacaatgcggtcaaccttagctgc
aagtattcctacaatctcttctcaagggagttccgggcatcccttcacaaaggactggat
agtgctgtggaagtctgtgttgtatatgggaattactcccagcagcttcaggtttactca
aaaacggggttcaactgtgatgggaaattgggcaatgaatcagtgacattctacctccag
aatttgtatgttaaccaaacagatatttacttctgcaaaattgaagttatgtatcctcct
ccttacctagacaatgagaagagcaatggaaccattatccatgtgaaagggaaacacctt
tgtccaagtcccctatttcccggaccttctaagcccttttgggtgctggtggtggttggt
ggagtcctggcttgctatagcttgctagtaacagtggcctttattattttctgggtgagg
agtaagaggagcaggctcctgcacagtgactacatgaacatgactccccgccgccccggg
cccacccgcaagcattaccagccctatgccccaccacgcgacttcgcagcctatcgctcc
tga