@article{37caf41c17f54fee9316520e23f3bcfb,
title = "Catalytic site conformations in human PNP by 19F-NMR and crystallography",
abstract = "Purine nucleoside phosphorylase (PNP) is a target for leukemia, gout, and autoimmune disorders. Dynamic motion of catalytic site loops has been implicated in catalysis, but experimental evidence was lacking. We replaced catalytic site groups His257 or His64 with 6-fluoro-tryptophan (6FW) as site-specific NMR probes. Conformational adjustments in the 6FW-His257-helical and His64-6FW-loop regions were characterized in PNP phosphate-bound enzyme and in complexes with catalytic site ligands, including transition state analogs. Chemical shift and line-shape changes associated with these complexes revealed dynamic coexistence of several conformational states in these regions in phosphate-bound enzyme and altered or single conformations in other complexes. These conformations were also characterized by X-ray crystallography. Specific 19F-Trp labels and X-ray crystallography provide multidimensional characterization of conformational states for free, catalytic, and inhibited complexes of human PNP.",
author = "Javier Suarez and Haapalainen, {Antti M.} and Cahill, {Sean M.} and Ho, {Meng Chiao} and Funing Yan and Almo, {Steven C.} and Schramm, {Vern L.}",
note = "Funding Information: This work was supported by the National Institutes of Health (NIH) (research grants GM068036 and GM041916 to V.L.S.), a fellowship from the Sigrid Jus{\'e}lius Foundation (to A.M.H.), and the National Institute of General Medical Sciences of the National Institutes of Health under award number K12GM102779 (J.S.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Data for this study were measured at the beamline X29A at the Case Center for Synchrotron Biosciences (CCSB), located at the National Synchrotron Light Source at Brookhaven National Laboratories, New York. The collection of this data was made possible by the Center for Synchrotron Biosciences grant (P30-EB-009998) from the National Institute of Biomedical Imaging and Bioengineering (NIBIB). The authors thank Drs. Peter C. Tyler and Gary B. Evans of Industrial Research, Ltd. for the generous gift of DADMeImmG and DADMeImmH and also Dr. Patskovsky for collecting the data sets for PDB ID codes 4EAR and 4GKA . ",
year = "2013",
month = feb,
day = "21",
doi = "10.1016/j.chembiol.2013.01.009",
language = "English (US)",
volume = "20",
pages = "212--222",
journal = "Cell Chemical Biology",
issn = "2451-9448",
publisher = "Elsevier Inc.",
number = "2",
}