INSIGHTS INTO THE BINDING AND CATALYTIC MECHANISMS OF BACILLUS THURINGIENSIS LACTONASE AND INTERACTIONS OF A PTEN-BINDING INHIBITORY PEPTIDE

Charendoff, Marc Neil 1968-

INSIGHTS INTO THE BINDING AND CATALYTIC MECHANISMS OF BACILLUS THURINGIENSIS LACTONASE AND INTERACTIONS OF A PTEN-BINDING INHIBITORY PEPTIDE

dc.contributor.advisor	Briggs, James M.
dc.contributor.committeeMember	Willson, Richard C.
dc.contributor.committeeMember	Bittner, Eric R.
dc.contributor.committeeMember	Widger, William R.
dc.contributor.committeeMember	Yeo, Hye-Jeong
dc.creator	Charendoff, Marc Neil 1968-
dc.date.accessioned	2013-07-16T15:50:02Z
dc.date.available	2013-07-16T15:50:02Z
dc.date.created	May 2013
dc.date.issued	2013-05
dc.date.updated	2013-07-16T15:50:08Z
dc.description.abstract	The lactonase enzyme (AiiA) produced by Bacillus thuringiensis (B. thuringiensis) serves to degrade autoinducer-1 (AI-1) signaling molecules in what is an evolved mechanism by which allows B. thuringiensis to better compete with other bacteria. Bioassays have been previously performed to determine whether the AI-1 aliphatic tail lengths have any effect on AiiA’s bioactivity; however, data to date are conflicting. To investigate these questions, multiple molecular dynamics simulations were performed across a family of seven acylated homoserine lactones (AHL) along with their associated intermediate and product states. Distance analyses and interaction energy analyses were performed to investigate current bioassay data. Our simulations are consistent with experimental studies showing that AiiA degrades AHLs in a tail length independent manner. Also, a proposed putative oxyanion hole function of Y194 toward the substrate is not observed in any of the reactant or product state simulation trajectories. However, Y194 does seem to show efficacy in stabilizing the intermediate state. Last, we argue through ionization state analyses, that proton-shuttling necessary for catalytic activity is possibly mediated by both water- and substrate-based, intra-molecular proton transfer. Based on this argument, an alternate catalytic mechanism is proposed. Drug dependence, or addiction ultimately described as the maladaptation of a neurochemical reward pathway that is normally used to reinforce behaviors that promote an organism’s survival and/or propagation (e.g., high calorie food seeking and sexual drive). These pathways are mediated via dopaminergic VTA-NAc neuronal networks. The molecular basis for this interaction has been shown to rely on a 5HT-2cR:PTEN interaction via the 3L4F-F1 fragment. The nature of the interaction is unknown. In this work a series of REMD runs are designed to generate candidate conformations that might exist under physiological conditions. These candidates are then subjected to exhaustive six-dimensional, coarse-grained docking simulations against the PTEN protein to produce a myriad of potential docking sites. From these dockings the top scoring poses are observed to point to a single binding site that in turn lend themselves to spectroscopic validation.
dc.description.department	Biology and Biochemistry, Department of
dc.format.digitalOrigin	born digital
dc.format.mimetype	application/pdf
dc.identifier.uri	http://hdl.handle.net/10657/399
dc.language.iso	eng
dc.rights	The author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subject	Quorum signaling
dc.subject	Quorum sensing
dc.subject	Serotonin
dc.subject	Dopamine
dc.subject	PTEN
dc.subject	AHL
dc.subject	HSL lactonase
dc.subject	5-HT2c receptor
dc.subject.lcsh	Biochemistry
dc.title	INSIGHTS INTO THE BINDING AND CATALYTIC MECHANISMS OF BACILLUS THURINGIENSIS LACTONASE AND INTERACTIONS OF A PTEN-BINDING INHIBITORY PEPTIDE
dc.type.dcmi	Text
dc.type.genre	Thesis
thesis.degree.college	College of Natural Sciences and Mathematics
thesis.degree.department	Biology and Biochemistry, Department of
thesis.degree.discipline	Biochemistry
thesis.degree.grantor	University of Houston
thesis.degree.level	Doctoral
thesis.degree.name	Doctor of Philosophy