2V2D

The A178L mutation in the C-terminal hinge of the flexible loop-6 of triosephosphate isomerase (TIM) induces a more closed conformation of this hinge region in dimeric and monomeric TIM

Summary for 2V2D

• Entry DOI: 10.2210/pdb2v2d/pdb
• Related: 1AG1 1DKW 1IIG 1IIH 1KV5 1ML1 1MSS 1MTM 1TPD 1TPE 1TPF 1TRD 1TRI 1TSI 1TTI 1TTJ 2J24 2J27 2V0T 2V2C 3TIM 4TIM 5TIM 6TIM
• Descriptor: TRIOSEPHOSPHATE ISOMERASE GLYCOSOMAL, PHOSPHATE ION (3 entities in total)
• Functional Keywords: gluconeogenesis, lipid synthesis, engineering, pentose shunt, point mutation, tim, a178l, loop6, hinge, loop-6, enzyme, isomerase, fatty acid biosynthesis, triosephosphate isomerase, glycosome, monomeric, tim-barrel, glycolysis
• Biological source: TRYPANOSOMA BRUCEI BRUCEI
• Total number of polymer chains: 1
• Total formula weight: 26170.80

Authors

Alahuhta, M.,Casteleijn, M.G.,Neubauer, P.,Wierenga, R.K. (deposition date: 2007-06-05, release date: 2008-02-19, Last modification date: 2023-12-13)

Primary citation

Alahuhta, M.,Casteleijn, M.G.,Neubauer, P.,Wierenga, R.K.
Structural Studies Show that the A178L Mutation in the C-Terminal Hinge of the Catalytic Loop-6 of Triosephosphate Isomerase (Tim) Induces a Closed- Like Conformation in Dimeric and Monomeric Tim.
Acta Crystallogr.,Sect.D, 64:178-, 2008

PubMed Abstract: The flexible catalytic loop, loop-6, of TIM has evolved to preferably be open in the unliganded state and to preferably be closed in the liganded state. The N-terminal and C-terminal hinges of this loop are important for its opening/closing mechanism. In this study, a small conserved C-terminal hinge residue, Ala178, has been mutated into a residue with a larger side chain, Leu178. This mutation has been made in the dimeric trypanosomal wild-type TIM (wtTIM) and in its mutated catalytically competent monomeric variant (ml1TIM). The variants are referred to as A178L and ml1A178L, respectively. Crystal structures have been determined of unliganded A178L (at 2.2 A), liganded A178L (at 1.89 A), unliganded ml1A178L (at 2.3 A) and liganded ml1A178L (at 1.18 A) using the transition-state analogue 2-phosphoglycolate as a ligand. Structural characterization of the two variants shows that this mutation favours the closed conformation of the C-terminal hinge region, even in the absence of ligand. In the structure of the unliganded A178L variant a range of new loop-6 conformations are observed, including subunits in which the tip of loop-6 is completely disordered. The catalytic efficiency of A178L is lower than that of wtTIM, which correlates with the structural differences between the apo forms of wtTIM and A178L, in particular the more disordered loop-6 in the structure of unliganded A178L. In the liganded structures of A178L and ml1A178L the structural differences induced by the mutation are minimal. Structural characterization of the ml1A178L variant highlights its structural plasticity.

PubMed: 18219118
DOI: 10.1107/S0907444907059021

Experimental method

X-RAY DIFFRACTION (2.3 Å)