Soetens O, Crabeel M, El Moualij B, Duyckaerts C, Sluse F
Department of Microbiology, Vrije Universiteit Brussel and Vlaams Interuniversitair Instituut voor Biotechnologie, c/o Research Institute of COOVI, Brussels, Belgium.
Eur J Biochem. 1998 Dec 1;258(2):702-9. doi: 10.1046/j.1432-1327.1998.2580702.x.
In this work we have characterised the transport of L-arginine and L-ornithine into mitochondria isolated from a wild-type Saccharomyces cerevisiae strain and an isogenic arg11 knock-out mutant. The Arg11 protein (Arg11p) is a mitochondrial carrier required for arginine biosynthesis [Crabeel, M., Soetens, O., De Rijcke, M., Pratiwi, R. & Pankiewicz, R. (1996) J. Biol. Chem. 271, 25011-25019]. Reconstitution experiments have confirmed that it is an L-ornithine carrier also transporting L-arginine and L-lysine by order of decreasing affinity, but not L-histidine [Palmieri, L., De Marco, V., Iacobazzi, V., Palmieri, F., Runswick, M. & Walker, J. (1997) FEBS Lett. 410, 447-451]. Evidence is presented here that the mitochondrial inner membrane contains an L-arginine and L-ornithine transporting system distinct from Arg11p, in keeping with the arginine leaky phenotype of arg11 knock-out mutants. The newly characterised carrier, which we propose to name Bac1p (basic amino acid carrier), behaves as an antiporter catalysing the electroneutral exchange of the basic amino acids L-arginine, L-lysine, L-ornithine and L-histidine and displays the highest affinity for L-arginine (Km of 30 microM). L-Arginine uptake has a pH optimum in the range of 7.5-9 and is inhibited by several sulphydryl reagents, by pyridoxal 5'-phosphate and by cations.
在本研究中，我们对从野生型酿酒酵母菌株和同基因arg11敲除突变体中分离出的线粒体摄取L-精氨酸和L-鸟氨酸的过程进行了表征。Arg11蛋白（Arg11p）是精氨酸生物合成所需的线粒体载体[Crabeel, M., Soetens, O., De Rijcke, M., Pratiwi, R. & Pankiewicz, R. (1996) J. Biol. Chem. 271, 25011 - 25019]。重组实验已证实它是一种L-鸟氨酸载体，也能转运L-精氨酸和L-赖氨酸，亲和力依次降低，但不转运L-组氨酸[Palmieri, L., De Marco, V., Iacobazzi, V., Palmieri, F., Runswick, M. & Walker, J. (1997) FEBS Lett. 410, 447 - 451]。本文提供的证据表明，线粒体内膜含有一个与Arg11p不同的L-精氨酸和L-鸟氨酸转运系统，这与arg11敲除突变体的精氨酸渗漏表型一致。我们提议将新鉴定的载体命名为Bac1p（碱性氨基酸载体），它作为一种反向转运体，催化碱性氨基酸L-精氨酸、L-赖氨酸、L-鸟氨酸和L-组氨酸的电中性交换，对L-精氨酸显示出最高亲和力（Km为30 microM）。L-精氨酸摄取的最适pH范围为7.5 - 9，并受到几种巯基试剂、5'-磷酸吡哆醛和阳离子的抑制。
