caa a22 4500 475744101 CHVBK 20180406123508.0 cr unu---uuuuu 170329e20001001xx s 000 0 eng 10.1023/A:1007102402925 doi (NATIONALLICENCE)springer-10.1023/A:1007102402925 Stability and Release Requirements of the Complexes of GroEL with Two Homologous Mammalian Aminotransferases [Elektronische Daten] [Serge Scherrer, Ana Iriarte, Marino Martinez-Carrion] The mitochondrial (mAAT) and cytosolic (cAAT) homologous isozymes of aspartate aminotransferase are two relatively large proteins that in their nonnative states interact very differently with GroEL. MgATP alone can increase the rate of GroEL-assisted reactivation of cAAT, yet the presence of GroES is mandatory for mAAT. Addition of an excess of a denatured substrate accelerates reactivation of cAAT in the presence of GroEL, but has no effect on mAAT. These competition studies suggest that the more stringent substrate mAAT forms a thermodynamically stable complex with GroEL, while rebinding affects the slow reactivation kinetics of cAAT with GroEL alone. However, the competitor appears to accelerate the release of cAAT from GroEL, most likely by displacing bound cAAT from the GroEL cavity. Moreover, cAAT, but not mAAT, shows a time-dependent increase in protease resistance while bound to GroEL at low temperature. These results suggest that folding and release of cAAT from GroEL in the absence of cofactors may occur stepwise with certain interactions being broken and reformed until the protein escapes binding. The distinct behavior of these two isozymes most likely results from differences in the structure of the nonnative states that bind to GroEL. Plenum Publishing Corporation, 2000 Aspartate aminotransferase nationallicence mitochondrial and cytosolic isozymes nationallicence GroEL nationallicence protein folding nationallicence Scherrer Serge Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110-2499, Kansas City, Missouri aut Iriarte Ana Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110-2499, Kansas City, Missouri aut Martinez-Carrion Marino Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110-2499, Kansas City, Missouri aut Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/7(2000-10-01), 591-602 0277-8033 19:7<591 2000 19 10930 https://doi.org/10.1023/A:1007102402925 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1007102402925 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Scherrer Serge Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110-2499, Kansas City, Missouri aut NATIONALLICENCE 700 1- Iriarte Ana Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110-2499, Kansas City, Missouri aut NATIONALLICENCE 700 1- Martinez-Carrion Marino Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 64110-2499, Kansas City, Missouri aut NATIONALLICENCE 773 0- Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/7(2000-10-01), 591-602 0277-8033 19:7<591 2000 19 10930 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer