Examining the role of protein structural dynamics in drug resistance inMycobacterium tuberculosis

Abstract

2D-IR spectroscopy reveals a role for protein structural dynamics in antimicrobial-resistance.

Measuring proteins in H2O with 2D-IR spectroscopy

“…Infrared spectroscopy is sensitive to molecular structure, but its application to proteins is hindered by the broad nature of the amide I band, essentially the CO stretching mode of the peptide link. 2D-IR spectroscopy overcomes this problem by measuring vibrational couplings between peptide units in macromolecular structures and the 2D-IR amide I signal is diagnostic of secondary structure content and ligand binding 1–6. Water is an obstacle common to both IR absorption and 2D-IR spectroscopy.…”

The importance of the quaternary structure to represent conformational ensembles of the major Mycobacterium tuberculosis drug target

“…In previous works, the MtInhA enzyme has been used as a monomer in MM/MD simulations 9,34,35 , based on the assumption that the binding sites are independent of each other and thereby the tertiary structure could represent the behavior of the biological structure in solution. However, based on our results, there is a statistically significant difference between the conformational ensembles of tertiary and quaternary structures.…”

Two-dimensional infrared spectroscopy: an emerging analytical tool?

“…A study of inhibitor binding to the InhA enzyme, a component of the fatty acid synthase pathway responsible for maintaining cell wall integrity in Mycobacterium tuberculosis and a validated drug target, showed that changes in the off-diagonal region of the amide I 2D-IR band correlated with drug binding and enzyme inhibition. 13 In particular, this component of the 2D-IR amide I lineshape was less strongly affected in mutations of InhA found in drug resistant forms of the bacterium. Combining spectroscopy with modelling, it was demonstrated that the 2D-IR signal was responding to changes in dynamics of the protein backbone caused by drug binding, a particularly subtle effect given that no large scale structure change accompanies binding.…”

“…Combining spectroscopy with modelling, it was demonstrated that the 2D-IR signal was responding to changes in dynamics of the protein backbone caused by drug binding, a particularly subtle effect given that no large scale structure change accompanies binding. 13 This shows the ability of 2D-IR to go beyond the structure function relationship, providing new insight. Once again, this was a detailed spectroscopic study, but it can be seen that the 2D-IR signature of 'effective inhibition' provides the basis for a screening study of new prospective ligands and hence a route by which 2D-IR can contribute to the drug design process.…”

“…Of relevance to the analytical science community, this ability to measure vibrational couplings and dynamics means that each molecule produces a unique two dimensional pattern of peaks. As well as being highly sensitive to small changes in biomolecular structure in a way that IR absorption cannot match, for example upon ligand binding to proteins or DNA, [12][13][14][15] , these patterns can be diagnostic of molecules in complex mixtures. These strengths create the potential for 2D-IR to be applied analytically, but this has only been realised by recent developments in ultrafast laser technology and mid-IR pulse Shaping, along with developments in data handling and analysis, that have allowed rapid scanning 2D-IR instruments capable of recording a 2D-IR spectrum in a matter of seconds to be created.…”