3E76

Crystal structure of Wild-type GroEL with bound Thallium ions

Summary for 3E76

• Entry DOI: 10.2210/pdb3e76/pdb
• Related: 1kp8 1xck 2nwc
• Descriptor: 60 kDa chaperonin, PHOSPHOTHIOPHOSPHORIC ACID-ADENYLATE ESTER, THALLIUM (I) ION, ... (4 entities in total)
• Functional Keywords: groel, hsp60, chaperonin, thallium, atp-binding, chaperone, nucleotide-binding
• Biological source: Escherichia coli UTI89
• Cellular location: Cytoplasm (By similarity): Q1R3B6
• Total number of polymer chains: 14
• Total formula weight: 818714.40

Authors

Kiser, P.D.,Lorimer, G.H.,Palczewski, K. (deposition date: 2008-08-17, release date: 2009-08-25, Last modification date: 2023-08-30)

Primary citation

Kiser, P.D.,Lorimer, G.H.,Palczewski, K.
Use of thallium to identify monovalent cation binding sites in GroEL.
Acta Crystallogr.,Sect.F, 65:967-971, 2009

PubMed Abstract: GroEL is a bacterial chaperone protein that assembles into a homotetradecameric complex exhibiting D(7) symmetry and utilizes the co-chaperone protein GroES and ATP hydrolysis to assist in the proper folding of a variety of cytosolic proteins. GroEL utilizes two metal cofactors, Mg(2+) and K(+), to bind and hydrolyze ATP. A K(+)-binding site has been proposed to be located next to the nucleotide-binding site, but the available structural data do not firmly support this conclusion. Moreover, more than one functionally significant K(+)-binding site may exist within GroEL. Because K(+) has important and complex effects on GroEL activity and is involved in both positive (intra-ring) and negative (inter-ring) cooperativity for ATP hydrolysis, it is important to determine the exact location of these cation-binding site(s) within GroEL. In this study, the K(+) mimetic Tl(+) was incorporated into GroEL crystals, a moderately redundant 3.94 A resolution X-ray diffraction data set was collected from a single crystal and the strong anomalous scattering signal from the thallium ion was used to identify monovalent cation-binding sites. The results confirmed the previously proposed placement of K(+) next to the nucleotide-binding site and also identified additional binding sites that may be important for GroEL function and cooperativity. These findings also demonstrate the general usefulness of Tl(+) for the identification of monovalent cation-binding sites in protein crystal structures, even when the quality and resolution of the diffraction data are relatively low.

PubMed: 19851000
DOI: 10.1107/S1744309109032928

Experimental method

X-RAY DIFFRACTION (3.94 Å)