Nucleotide regulates the affinity of the bacterial chaperonin GroEL for protein substrates. GroEL binds protein substrates with high affinity in the absence of ATP and with low affinity in its presence. We report the crystal structure of (GroEL-KMgATP)(1 ...
Nucleotide regulates the affinity of the bacterial chaperonin GroEL for protein substrates. GroEL binds protein substrates with high affinity in the absence of ATP and with low affinity in its presence. We report the crystal structure of (GroEL-KMgATP)(14) refined to 2.0 A resolution in which the ATP triphosphate moiety is directly coordinated by both K(+) and Mg(2+). Upon the binding of KMgATP, we observe previously unnoticed domain rotations and a 102 degrees rotation of the apical domain surface helix I. Two major consequences are a large lateral displacement of, and a dramatic reduction of hydrophobicity in, the apical domain surface. These results provide a basis for the nucleotide-dependent regulation of protein substrate binding and suggest a mechanism for GroEL-assisted protein folding by forced unfolding.
Related Citations:
The 2.4 A Crystal Structure of the Bacterial Chaperonin GroEL Complexed with ATP Gamma S Boisvert, D.C., Wang, J., Otwinowski, Z., Horwich, A.L., Sigler, P.B. (1996) Nat Struct Biol 3: 170
The Crystal Structure of the Bacterial Chaperonin GroEL at 2.8 A Braig, K., Otwinowski, Z., Hegde, R., Boisvert, D.C., Joachimiak, A., Horwich, A.L., Sigler, P.B. (1994) Nature 371: 578
Conformational Variability in the Refined Structure of the Chaperonin GroEL at 2.8 A Resolution Braig, K., Adams, P.D., Brunger, A.T. (1995) Nat Struct Biol 2: 1083
The Crystal Structure of the Asymmetric GroEL-GroES-(ADP)7 Chaperonin Complex Xu, Z., Horwich, A.L., Sigler, P.B. (1997) Nature 388: 741
Organizational Affiliation:
Department of Molecular Biophysics and Biochemistry Yale University, 266 Whitney Avenue, Bass Center, Room 418, New Haven, CT 06520-8114, USA. wang@mail.csb.yale.edu
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