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1fxu
From Proteopedia
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| , resolution 2.20Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , and | ||||||
| Activity: | Purine-nucleoside phosphorylase, with EC number 2.4.2.1 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
PURINE NUCLEOSIDE PHOSPHORYLASE FROM CALF SPLEEN IN COMPLEX WITH N(7)-ACYCLOGUANOSINE INHIBITOR AND A PHOSPHATE ION
Overview
The calf spleen purine nucleoside phosphorylase (PNP) ternary complex with an N(7)-acycloguanosine inhibitor and a phosphate ion has been crystallized in the cubic space group P2(1)3, with unit-cell parameter a = 94.11 A and one monomer per asymmetric unit. X-ray diffraction data were collected using synchrotron radiation (Station X31, EMBL Outstation, DESY, Hamburg). The crystal structure was refined to a resolution of 2.2 A and R and R(free) values of 17.5 and 24.5%, respectively. The acyclonucleoside inhibitor is bound in the active site in an inverted ('upside-down') orientation of the purine base compared with natural substrates. The side chain of Asp243 forms two hydrogen bonds with the base ring: N(delta) donates a hydrogen to N(3) and O(delta) accepts a hydrogen from the guanine N(2)-amino group. N(1)--H of the base is hydrogen bonded to O(epsilon) of Glu201, while N(9) accepts a hydrogen bond from Thr242 O(gamma). In addition, a water molecule (W417) bridges the N(2)-amino group of the base and O(epsilon) of Glu201. In the phosphate-binding site, a phosphate ion is bound to Ser33, His64, Arg84, His86, Ala116 and Ser220. The acyclic chain of the N(7)-acycloguanosine inhibitor is in a folded conformation and together with a water molecule (W388) occupies the pentose-binding site, with possible hydrogen bonds to Tyr88 O(eta) and His257 N(delta 1). This new binding mode fully accounts for the previously observed substrate properties of 7-beta-D-ribofuranosides of hypoxanthine and guanine. It also provides a new starting point for the design of inhibitors of PNP for therapeutic and other applications.
About this Structure
1FXU is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
Calf spleen purine nucleoside phosphorylase: structure of its ternary complex with an N(7)-acycloguanosine inhibitor and a phosphate anion., Luic M, Koellner G, Shugar D, Saenger W, Bzowska A, Acta Crystallogr D Biol Crystallogr. 2001 Jan;57(Pt 1):30-6. PMID:11134924
Page seeded by OCA on Thu Mar 20 11:15:22 2008
