Specific sequence motifs of mitochondrial uncoupling proteins

We have searched for the exclusivity of common sequence motifs of the mitoc hondrial uncoupling proteins (UCP1, UCP2, UCP3, UCP4, BMCP1, and plant UCP [PUMP]) within the gene family of mitochondrial anion carrier proteins. The UCP-specific sequences, "UCP signatures", were found in the first, second, and fourth alpha-helices, First:Ala/Ser-Cys/Thr/n-n/Phe-Ala/Gly-[-]-n/Phe- n/Cys- Thr-Phe/n; second: Gly/Ala-Ile/Leu-Gln/X-[+]-NH-n/Cys-Ser/n-phi/X-n/ Ser-OH/Gly-n-[+]Ile/Met-Gly/Val-n/Thr; fourth: Pro-Asn/Thr-n-X-[+]-Asn/Ser/ Ala-n-ILe/Leu-n-Asn/Val-Cys/n-n/Thr-[-]n-n/Thr/Pro-OH/Val (n, nonpolar; phi , aromatic; +/-, charged residue), The second and part of the third signatu re are also present in the yeast dicarboxylate transporter. The UCP signatu re excluding BMCP1 was also found in the second matrix segment: [+](Pro/del -Leu/del)-[+]-phi-X-Gly/Ser-Thr/n-X-NH/[-]-Ala-phi. These UCP signatures ar e thought to be involved in fatty acid anion binding and translocation.