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Nested allosteric interactions in the cytoplasmic chaperonin containing TCP‐1
Author(s) -
Kafri Galit,
Willison Keith R.,
Horovitz Am
Publication year - 2001
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.44401
Subject(s) - chaperonin , allosteric regulation , cooperativity , groel , atp hydrolysis , cooperative binding , protein subunit , biophysics , chaperone (clinical) , chemistry , allosteric enzyme , biochemistry , biology , binding site , enzyme , protein folding , medicine , atpase , escherichia coli , pathology , gene
Initial rates of ATP hydrolysis by the chaperonin containing TCP‐1 (CCT) from bovine testis were measured as a function of ATP concentration. Two allosteric transitions are observed: one at relatively low concentrations of ATP (<100 μM) and the second at higher concentrations of ATP. The data suggest that CCT has positive intra‐ring cooperativity and negative inter‐ring cooperativity in ATP hydrolysis, with respect to ATP, as previously observed in the case of GroEL. It is shown that the relatively weak positive intra‐ring cooperativity found in the case of CCT may be due to heterogeneity in its subunit composition. Our results suggest that nested allosteric behavior may be common to chaperone double‐ring systems.