title: Preliminary joint X-ray and neutron protein crystallographic studies of ecDHFR complexed with folate and NADP+.
abstract: A crystal of Escherichia coli dihydrofolate reductase (ecDHFR) complexed with folate and NADP+ of 4×1.3×0.7 mm (3.6 mm3) in size was obtained by sequential application of microseeding and macroseeding. A neutron diffraction data set was collected to 2.0 Å resolution using the IMAGINE diffractometer at the High Flux Isotope Reactor within Oak Ridge National Laboratory. A 1.6 Å resolution X-ray data set was also collected from a smaller crystal at room temperature. The neutron and X-ray data were used together for joint refinement of the ecDHFR-folate-NADP+ ternary-complex structure in order to examine the protonation state, protein dynamics and solvent structure of the complex, furthering understanding of the catalytic mechanism.
authors.affiliation: Department of Biochemistry, College of Medicine, Yangzhou University, 11 HuaiHai Road, Yangzhou 225001, People's Republic of China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Wan
authors.affiliation: Biology and Soft Matter Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, USA.
authors.forename: Andrey Y
authors.initials: AY
authors.lastname: Kovalevsky
authors.affiliation: Department of Biochemistry/Redox Biology Center, University of Nebraska, 1901 Vine Street, Lincoln, NE 68588, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wilson
authors.affiliation: Department of Molecular Physiology and Biological Physics, University of Virginia, PO Box 800793, Charlottesville, VA 22908, USA.
authors.forename: Brad C
authors.initials: BC
authors.lastname: Bennett
authors.affiliation: Biology and Soft Matter Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Langan
authors.affiliation: Department of Pharmacology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Dealwis
mesh_terms: D003461:Crystallography / Q000379:methods*; D005492:Folic Acid / Q000737:chemistry*; D009249:NADP / Q000737:chemistry*; D009502:Neutrons; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry*; D014965:X-Rays
chemical_list: D009249:NADP; D005492:Folic Acid; D013762:Tetrahydrofolate Dehydrogenase
keywords: Escherichia coli; dihydrofolate reductase; protonation state