Two parameters improve efficiency of mitochondrial uptake of adenylate kinase: decreased folding velocity and increased propensity of N‐terminal α‐helix formation

FEBS Letters

Korber, Dorothee¹  Zollner, Alfred¹  Bandlow, Wolfhard¹  Strobel, Gertrud¹  Angermayr, Michaela¹ 

[1] Institut für Genetik und Mikrobiologie der Universität München, Maria-Ward-Straße 1a, D-80638 Munich, Germany

关键词: Adenylate kinase;    Protein folding;    Mitochondrial import;    Sub-mitochondrial sorting;    Saccharomyces cerevisiae;    AK;    adenylate kinase;    Aky2p;    yeast major adenylate kinase;    AKY2;    gene encoding Aky2p;    FN;    family numbering;   

DOI  :  10.1016/S0014-5793(01)03122-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The long isoform of eukaryotic adenylate kinase has a dual subcellular location in the cytoplasm and in the mitochondrial intermembrane space. Protein sequences and modifications are identical in both locations. In yeast, the bulk of the major form of adenylate kinase (Aky2p) is in the cytoplasm and, in the steady state, only 5–8% is sorted to the mitochondrial intermembrane space. Since the reasons for exclusion from mitochondrial import are unclear, we have constructed aky2 mutants with elevated mitochondrial uptake efficiency of Aky2p in vivo and in vitro. We have analyzed the effect of the mutations on secondary structure prediction in silico and have tested folding velocity and folding stability. One type of mutants displayed decreased proteolytic stability and retarded renaturation kinetics after chaotropic denaturation implying that deterioration of folding leads to prolonged presentation of target information to mitochondrial import receptors, thereby effecting improved uptake. In a second type of mutants, increased import efficiency was correlated with an increased probability of formation of an α-helix with increased amphipathic moment at the N-terminus suggesting that targeting interactions with mitochondrial import receptors had been improved at the level of binding affinity.

【 授权许可】

Unknown