4oxy
From Proteopedia
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== Structural highlights == | == Structural highlights == | ||
[[4oxy]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4OXY OCA]. <br> | [[4oxy]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4OXY OCA]. <br> | ||
| - | <b>Related:</b> [[4ohu|4ohu]], [[4oxk|4oxk]], [[4oxn|4oxn]], [[2x23|2x23]], [[2b36|2b36]]<br> | + | <b>[[Ligand|Ligands:]]</b> <scene name='pdbligand=1TN:5-HEXYL-2-(2-NITROPHENOXY)PHENOL'>1TN</scene>, <scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</scene><br> |
| + | <b>[[Related_structure|Related:]]</b> [[4ohu|4ohu]], [[4oxk|4oxk]], [[4oxn|4oxn]], [[2x23|2x23]], [[2b36|2b36]]<br> | ||
<b>Activity:</b> <span class='plainlinks'>[http://en.wikipedia.org/wiki/Glucokinase Glucokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.2 2.7.1.2] </span><br> | <b>Activity:</b> <span class='plainlinks'>[http://en.wikipedia.org/wiki/Glucokinase Glucokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.2 2.7.1.2] </span><br> | ||
| + | <b>Resources:</b> <span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4oxy FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4oxy OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4oxy RCSB], [http://www.ebi.ac.uk/pdbsum/4oxy PDBsum]</span><br> | ||
== Publication Abstract from PubMed == | == Publication Abstract from PubMed == | ||
Slow-onset enzyme inhibitors are of great interest for drug discovery programs since the slow dissociation of the inhibitor from the drug-target complex results in sustained target occupancy leading to improved pharmacodynamics. However, the structural basis for slow-onset inhibition is often not fully understood, hindering the development of structure-kinetic relationships and the rational optimization of drug-target residence time. Previously we demonstrated that slow-onset inhibition of the Mycobacterium tuberculosis enoyl-ACP reductase InhA correlated with motions of a substrate-binding loop (SBL) near the active site. In the present work, X-ray crystallography and molecular dynamics simulations have been used to map the structural and energetic changes of the SBL that occur upon enzyme inhibition. Helix-6 within the SBL adopts an open conformation when the inhibitor structure or binding kinetics is substrate-like. In contrast, slow-onset inhibition results in large-scale local refolding in which helix-6 adopts a closed conformation not normally populated during substrate turnover. The open and closed conformations of helix-6 are hypothesized to represent the EI and EI* states on the two-step induced-fit reaction coordinate for enzyme inhibition. These two states were used as the end points for nudged elastic band molecular dynamics simulations resulting in two-dimensional potential energy profiles that reveal the barrier between EI and EI*, thus rationalizing the binding kinetics observed with different inhibitors. Our findings indicate that the structural basis for slow-onset kinetics can be understood once the structures of both EI and EI* have been identified, thus providing a starting point for the rational control of enzyme-inhibitor binding kinetics. | Slow-onset enzyme inhibitors are of great interest for drug discovery programs since the slow dissociation of the inhibitor from the drug-target complex results in sustained target occupancy leading to improved pharmacodynamics. However, the structural basis for slow-onset inhibition is often not fully understood, hindering the development of structure-kinetic relationships and the rational optimization of drug-target residence time. Previously we demonstrated that slow-onset inhibition of the Mycobacterium tuberculosis enoyl-ACP reductase InhA correlated with motions of a substrate-binding loop (SBL) near the active site. In the present work, X-ray crystallography and molecular dynamics simulations have been used to map the structural and energetic changes of the SBL that occur upon enzyme inhibition. Helix-6 within the SBL adopts an open conformation when the inhibitor structure or binding kinetics is substrate-like. In contrast, slow-onset inhibition results in large-scale local refolding in which helix-6 adopts a closed conformation not normally populated during substrate turnover. The open and closed conformations of helix-6 are hypothesized to represent the EI and EI* states on the two-step induced-fit reaction coordinate for enzyme inhibition. These two states were used as the end points for nudged elastic band molecular dynamics simulations resulting in two-dimensional potential energy profiles that reveal the barrier between EI and EI*, thus rationalizing the binding kinetics observed with different inhibitors. Our findings indicate that the structural basis for slow-onset kinetics can be understood once the structures of both EI and EI* have been identified, thus providing a starting point for the rational control of enzyme-inhibitor binding kinetics. | ||
Revision as of 10:05, 30 April 2014
Substrate-binding loop movement with inhibitor PT10 in the tetrameric Mycobacterium tuberculosis enoyl-ACP reductase InhA
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