In April 2024, the FASTA files of the sequences in the BLAST databases will no longer be available on the FTP site. You can generate FASTA files yourself from the formatted BLAST databases by using the BLAST utility blastdbcmd that comes with the standalone BLAST programs. This also provides you the flexibility to generate organism-specific FASTA files using NCBI's taxonomy IDs for specific organisms or groups.

See NCBI Insights for more details.