1WCR

Trimeric Structure of the Enzyme IIA from Escherichia coli Phosphotransferase System Specific for N,N'-Diacetylchitobiose

Summary for 1WCR

• Entry DOI: 10.2210/pdb1wcr/pdb
• Descriptor: PTS SYSTEM, N, N'-DIACETYLCHITOBIOSE-SPECIFIC IIA COMPONENT (1 entity in total)
• Functional Keywords: iia, pts, mutagenesis, chitobiose, transferase, sugar transport, phosphotransferase
• Biological source: ESCHERICHIA COLI
• Total number of polymer chains: 3
• Total formula weight: 33768.56

Authors

Tang, C.,Clore, G.M. (deposition date: 2004-11-19, release date: 2005-01-19, Last modification date: 2024-05-15)

Primary citation

Tang, C.,Williams, D.C.,Ghirlando, R.,Clore, G.M.
Solution Structure of Enzyme Iiachitobiose from the N,N'-Diacetylchitobiose Branch of the Escherichia Coli Phosphotransferase System
J.Biol.Chem., 280:11770-, 2005

PubMed Abstract: The solution structure of trimeric Escherichia coli enzyme IIA(Chb) (34 kDa), a component of the N,N'-diacetylchitobiose/lactose branch of the phosphotransferase signal transduction system, has been determined by NMR spectroscopy. Backbone residual dipolar couplings were used to provide long range orientational restraints, and long range (|i - j| > or = 5 residues) nuclear Overhauser enhancement restraints were derived exclusively from samples in which at least one subunit was 15N/13C/2H/(Val-Leu-Ile)-methyl-protonated. Each subunit consists of a three-helix bundle. Hydrophobic residues lining helix 3 of each subunit are largely responsible for the formation of a parallel coiled-coil trimer. The active site histidines (His-89 from each subunit) are located in three symmetrically placed deep crevices located at the interface of two adjacent subunits (A and C, C and B, and B and A). Partially shielded from bulk solvent, structural modeling suggests that phosphorylated His-89 is stabilized by electrostatic interactions with the side chains of His-93 from the same subunit and Gln-91 from the adjacent subunit. Comparison with the x-ray structure of Lactobacillus lactis IIA(Lac) reveals some substantial structural differences, particularly in regard to helix 3, which exhibits a 40 degrees kink in IIA(Lac) versus a 7 degrees bend in IIA(Chb). This is associated with the presence of an unusually large (230-angstroms3) buried hydrophobic cavity at the trimer interface in IIA(Lac) that is reduced to only 45 angstroms3) in IIA(Chb).

PubMed: 15654077
DOI: 10.1074/JBC.M414300200

Experimental method

SOLUTION NMR