Table 1.

Identification of HIV-1 Tat and LTR sequences co-linear to CCR5- and CXCR4-utilizing Env-V3 sequences defined by Web-PSSM scoring

Genomic region	CCR5	CXCR4
gp120	1678	52
Tat	504	31
LTR	615	35

HIV-1 amino acid sequences for gp120 and Tat and nucleotide sequences for LTR were classified as being derived from CCR5- or CXCR4-utilizing genomes according to Web-PSSM prediction scores utilizing the Env-V3 sequence. Sequences with intermediate scores PSSM scores are derived from R5, X4, or dual-tropic X4/R5 viruses and were not included in further analysis