2hcj: Difference between revisions

[[Image:2hcj.jpg|left|200px]]<br /><applet load="2hcj" size="350" color="white" frame="true" align="right" spinBox="true"  

Two crystal forms of a complex between trypsin-modified elongation factor Tu-MgGDP from Escherichia coli and the antibiotic tetracycline have been solved by X-ray diffraction analysis to resolutions of 2.8 and 2.1 A, respectively. In the P2(1) form, cocrystals were grown from a solution mixture of the protein and tetracycline. Six copies of the trypsin-modified EF-Tu-MgGDP-tetracycline complex are arranged as three sets of dimers in the asymmetric unit. In the second crystal form, tetracycline was diffused into P4(3)2(1)2 crystals, resulting in a monomeric complex in the asymmetric unit. Atomic coordinates have been refined to crystallographic R factors of 18.0% for the P2(1) form and 20.0% for the P4(3)2(1)2 form. In both complexes, tetracycline makes significant interactions with the GTPase active site of EF-Tu. The phenoldiketone moiety of tetracycline interacts directly with the Mg(2+), the alpha-phosphate group of GDP and two amino acids, Thr25 and Asp80, which are conserved in the GX(4)GKS/T and DX(2)G sequence motifs found in all GTPases and many ATPases. The molecular complementarity, previously unrecognized between invariant groups present in all GTPase/ATPases and the active moiety of tetracycline, may have wide-ranging implications for all drugs containing the phenoldiketone moiety as well as for the design of new compounds targeted against a broad range of GTPases or ATPases.

2HCJ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=NA:'>NA</scene>, <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=TAC:'>TAC</scene>, <scene name='pdbligand=GDP:'>GDP</scene> and <scene name='pdbligand=GLV:'>GLV</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2HCJ OCA].  

[[Category: Heffron, S E.]]

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