3ip0

From Proteopedia

Crystal structure of E. coli HPPK in complex with MgAMPCPP and 6-hydroxymethylpterin/6-carboxypterin

PDB ID 3ip0

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Structural highlights

3ip0 is a 1 chain structure with sequence from Escherichia coli K-12. This structure supersedes the now removed PDB entries 3h4a and 1f9y. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 0.89Å
Ligands:	, , , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

HPPK_ECOLI

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the pyrophosphoryl transfer from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP), the first reaction in the folate biosynthetic pathway. Arginine residues 82 and 92, strictly conserved in 35 HPPK sequences, play dynamic roles in the catalytic cycle of the enzyme. At 0.89-A resolution, two distinct conformations are observed for each of the two residues in the crystal structure of the wild-type HPPK in complex with two HP variants, two Mg(2+) ions, and an ATP analogue. Structural information suggests that R92 first binds to the alpha-phosphate group of ATP and then shifts to interact with the beta-phosphate as R82, which initially does not bind to ATP, moves in and binds to alpha-phosphate when the pyrophosphoryl transfer is about to occur. The dynamic roles of R82 and R92 are further elucidated by five more crystal structures of two mutant proteins, R82A and R92A, with and without bound ligands. Two oxidized forms of HP are observed with an occupancy ratio of 0.50:0.50 in the 0.89-A structure. The oxidation of HP has significant impact on its binding to the protein as well as the conformation of nearby residue W89.

Dynamic roles of arginine residues 82 and 92 of Escherichia coli 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase: crystallographic studies.,Blaszczyk J, Li Y, Shi G, Yan H, Ji X Biochemistry. 2003 Feb 18;42(6):1573-80. PMID:12578370^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Blaszczyk J, Li Y, Shi G, Yan H, Ji X. Dynamic roles of arginine residues 82 and 92 of Escherichia coli 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase: crystallographic studies. Biochemistry. 2003 Feb 18;42(6):1573-80. PMID:12578370 doi:10.1021/bi0267994