1X84

IPP isomerase (wt) reacted with (S)-bromohydrine of IPP

Summary for 1X84

• Entry DOI: 10.2210/pdb1x84/pdb
• Related: 1PPV 1X83
• Descriptor: Isopentenyl-diphosphate delta-isomerase, MANGANESE (II) ION, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: isomerase, complex
• Biological source: Escherichia coli
• Cellular location: Cytoplasm: Q46822
• Total number of polymer chains: 2
• Total formula weight: 43791.03

Authors

Wouters, J.,Oldfield, E. (deposition date: 2004-08-17, release date: 2005-01-25, Last modification date: 2011-07-13)

Primary citation

Wouters, J.,Yin, F.,Song, Y.,Zhang, Y.,Oudjama, Y.,Stalon, V.,Droogmans, L.,Morita, C.T.,Oldfield, E.
A Crystallographic Investigation of Phosphoantigen Binding to Isopentenyl Pyrophosphate/Dimethylallyl Pyrophosphate Isomerase
J.Am.Chem.Soc., 127:536-537, 2005

PubMed Abstract: We report the crystallographic structures of the potent phosphoantigens Phosphostim (the bromohydrin of isopentenyl pyrophosphate) and E-4-hydroxy-3-methyl-but-2-enyl pyrophosphate bound to the mevalonate pathway enzyme isopentenyl pyrophosphate/dimethylallyl pyrophosphate isomerase (IPPI). Racemic Phosphostim forms covalent complexes with IPPI: a 4-thioether with C67 and a 4-ester with E116. Only the E116 ester forms with the chiral species, S-Phosphostim, with the w.t. enzyme, while the C67 thioether forms with a mutant Y104F IPPI. The potent phosphoantigen HMBPP also binds to IPPI, but is only a weak ( approximately 50 muM) inhibitor. These results strongly support an SN2 reaction for inhibition of IPPI by Phosphostim, in contrast to the SN1 or concerted type of reaction found with epoxide inhibitors, which react at C-3, and are of general interest in the context of the development of novel mevalonate pathway inhibitors. They also provide clues as to the nature of the binding site of synthetic phosphoantigens in gammadelta T cell activation. In particular, both bromohydrin and epoxy phosphoantigens are potent, irreversible inhibitors of IPPI while HMBPP is only a weak inhibitor, ruling out an IPPI or IPPI-like target for HMBPP in gammadelta T cell activation.

PubMed: 15643873
DOI: 10.1021/ja040207i

Experimental method

X-RAY DIFFRACTION (1.78 Å)