The yeast mitochondrial ADP/ATP carrier functions as a monomer in mitochondrial membranes. Export

@article{citeulike:2354322, abstract = {Mitochondrial carriers are believed widely to be dimers both in structure and function. However, the structural fold is a barrel of six transmembrane alpha-helices without an obvious dimerisation interface. Here, we show by negative dominance studies that the yeast mitochondrial ADP/ATP carrier 2 from Saccharomyces cerevisiae (AAC2) is functional as a monomer in the mitochondrial membrane. Adenine nucleotide transport by wild-type AAC2 is inhibited by the sulfhydryl reagent 2-sulfonatoethyl-methanethiosulfonate (MTSES), whereas the activity of a mutant AAC2, devoid of cysteines, is unaffected. Wild-type and cysteine-less AAC2 were coexpressed in different molar ratios in yeast mitochondrial membranes. After addition of MTSES the residual transport activity correlated linearly with the fraction of cysteine-less carrier present in the membranes, and so the two versions functioned independently of each other. Also, the cysteine-less and wild-type carriers were purified separately, mixed in defined ratios and reconstituted into liposomes. Again, the residual transport activity in the presence of MTSES depended linearly on the amount of cysteine-less carrier. Thus, the entire transport cycle for ADP/ATP exchange is carried out by the monomer.}, address = {Medical Research Council, Dunn Human Nutrition Unit, Hills Road, Cambridge CB2 2XY, United Kingdom.}, author = {Bamber, L. and Harding, M. and Monn\'{e}, M. and Slotboom, D. J. and Kunji, E. R.}, citeulike-article-id = {2354322}, citeulike-linkout-0 = {http://dx.doi.org/10.1073/pnas.0703969104}, citeulike-linkout-1 = {http://www.pnas.org/content/104/26/10830.full.abstract}, citeulike-linkout-2 = {http://www.pnas.org/content/104/26/10830.full.full.pdf}, citeulike-linkout-3 = {http://view.ncbi.nlm.nih.gov/pubmed/17566106}, citeulike-linkout-4 = {http://www.hubmed.org/display.cgi?uids=17566106}, day = {26}, doi = {10.1073/pnas.0703969104}, issn = {1091-6490}, journal = {Proc Natl Acad Sci U S A}, keywords = {carriers, yeast}, month = {June}, number = {26}, pages = {10830--10834}, posted-at = {2009-04-27 12:01:56}, priority = {3}, title = {The yeast mitochondrial ADP/ATP carrier functions as a monomer in mitochondrial membranes.}, url = {http://dx.doi.org/10.1073/pnas.0703969104}, volume = {104}, year = {2007} }

TY - JOUR ID - citeulike:2354322 L3 - citeulike-article-id:2354322 N2 - Mitochondrial carriers are believed widely to be dimers both in structure and function. However, the structural fold is a barrel of six transmembrane alpha-helices without an obvious dimerisation interface. Here, we show by negative dominance studies that the yeast mitochondrial ADP/ATP carrier 2 from Saccharomyces cerevisiae (AAC2) is functional as a monomer in the mitochondrial membrane. Adenine nucleotide transport by wild-type AAC2 is inhibited by the sulfhydryl reagent 2-sulfonatoethyl-methanethiosulfonate (MTSES), whereas the activity of a mutant AAC2, devoid of cysteines, is unaffected. Wild-type and cysteine-less AAC2 were coexpressed in different molar ratios in yeast mitochondrial membranes. After addition of MTSES the residual transport activity correlated linearly with the fraction of cysteine-less carrier present in the membranes, and so the two versions functioned independently of each other. Also, the cysteine-less and wild-type carriers were purified separately, mixed in defined ratios and reconstituted into liposomes. Again, the residual transport activity in the presence of MTSES depended linearly on the amount of cysteine-less carrier. Thus, the entire transport cycle for ADP/ATP exchange is carried out by the monomer. IS - 26 JF - Proc Natl Acad Sci U S A SN - 1091-6490 AD - Medical Research Council, Dunn Human Nutrition Unit, Hills Road, Cambridge CB2 2XY, United Kingdom. EP - 10834 TI - The yeast mitochondrial ADP/ATP carrier functions as a monomer in mitochondrial membranes. VL - 104 SP - 10830 KW - carriers KW - yeast AU - Bamber, L AU - Harding, M AU - Monné, M AU - Slotboom, DJ AU - Kunji, ER PY - 2007/06/26/ UR - http://dx.doi.org/10.1073/pnas.0703969104 ER -