title: Active site coupling in Plasmodium falciparum GMP synthetase is triggered by domain rotation.
abstract: GMP synthetase (GMPS), a key enzyme in the purine biosynthetic pathway performs catalysis through a coordinated process across two catalytic pockets for which the mechanism remains unclear. Crystal structures of Plasmodium falciparum GMPS in conjunction with mutational and enzyme kinetic studies reported here provide evidence that an 85° rotation of the GATase domain is required for ammonia channelling and thus for the catalytic activity of this two-domain enzyme. We suggest that conformational changes in helix 371-375 holding catalytic residues and in loop 376-401 along the rotation trajectory trigger the different steps of catalysis, and establish the central role of Glu374 in allostery and inter-domain crosstalk. These studies reveal the mechanism of domain rotation and inter-domain communication, providing a molecular framework for the function of all single polypeptide GMPSs and form a solid basis for rational drug design targeting this therapeutically important enzyme.
authors.affiliation: BioCrystallography and Structural Biology of Therapeutic Targets Group, Molecular and Structural Bases of Infectious Systems, UMR5086 CNRS-University of Lyon 1, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Ballut
authors.affiliation: BioCrystallography and Structural Biology of Therapeutic Targets Group, Molecular and Structural Bases of Infectious Systems, UMR5086 CNRS-University of Lyon 1, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Violot
authors.affiliation: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Shivakumaraswamy
authors.affiliation: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
authors.forename: Lakshmi Prasoona
authors.initials: LP
authors.lastname: Thota
authors.affiliation: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
authors.forename: Manu
authors.initials: M
authors.lastname: Sathya
authors.affiliation: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
authors.forename: Jyothirmai
authors.initials: J
authors.lastname: Kunala
authors.affiliation: Laboratory of Biophysical Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Bauke W
authors.identifier: http://orcid.org/0000-0001-9731-6586
authors.initials: BW
authors.lastname: Dijkstra
authors.affiliation: Bioinformatics: Structures and Interactions Group, Molecular and Structural Bases of Infectious Systems, UMR5086 CNRS-University of Lyon 1, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Terreux
authors.affiliation: BioCrystallography and Structural Biology of Therapeutic Targets Group, Molecular and Structural Bases of Infectious Systems, UMR5086 CNRS-University of Lyon 1, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
authors.forename: Richard
authors.initials: R
authors.lastname: Haser
authors.affiliation: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
authors.forename: Hemalatha
authors.initials: H
authors.lastname: Balaram
authors.affiliation: BioCrystallography and Structural Biology of Therapeutic Targets Group, Molecular and Structural Bases of Infectious Systems, UMR5086 CNRS-University of Lyon 1, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
authors.forename: Nushin
authors.identifier: http://orcid.org/0000-0002-2245-2679
authors.initials: N
authors.lastname: Aghajari
mesh_terms: D019731:Carbon-Nitrogen Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D004798:Enzymes; D005973:Glutamine / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D010963:Plasmodium falciparum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D004798:Enzymes; D015800:Protozoan Proteins; D005973:Glutamine; D019731:Carbon-Nitrogen Ligases; C020828:GMP synthase (glutamine-hydrolyzing)