Unfolding the HIV-1 Reverse Transcriptase RNase H Domain - how to Lose a Molecular Tug-of-war

Unfolding the HIV-1 Reverse Transcriptase RNase H Domain - how to Lose a Molecular Tug-of-war

Author:

Publisher:

Published: 2016

Total Pages: 13

ISBN-13:

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Formation of the mature HIV-1 reverse transcriptase (RT) p66/p51 heterodimer requires subunit-specific processing of the p66/p66' homodimer precursor. Since the ribonuclease H (RH) domain contains an occult cleavage site located near its center, cleavage must occur either prior to folding or subsequent to unfolding. Recent NMR studies have identified a slow, subunit-specific RH domain unfolding process proposed to result from a residue tug-of-war between the polymerase and RH domains on the functionally inactive, p66' subunit. Here, we describe a structural comparison of the isolated RH domain with a domain swapped RH dimer that reveals several intrinsically destabilizing characteristics of the isolated domain that facilitate excursions of Tyr427 from its binding pocket and separation of helices B and D. These studies provide independent support for the subunit-selective RH domain unfolding pathway in which instability of the Tyr427 binding pocket facilitates its release followed by domain transfer, acting as a trigger for further RH domain destabilization and subsequent unfolding. As further support for this pathway, NMR studies demonstrate that addition of an RH active site-directed isoquinolone ligand retards the subunit-selective RH' domain unfolding behavior of the p66/p66' homodimer. As a result, this study demonstrates the feasibility of directly targeting RT maturation with therapeutics.


Unfolding the HIV-1 Reverse Transcriptase RNase H Domain {u2013} how to Lose a Molecular Tug-of-war

Unfolding the HIV-1 Reverse Transcriptase RNase H Domain {u2013} how to Lose a Molecular Tug-of-war

Author:

Publisher:

Published: 2016

Total Pages: 13

ISBN-13:

DOWNLOAD EBOOK

Formation of the mature HIV-1 reverse transcriptase (RT) p66/p51 heterodimer requires subunit-specific processing of the p66/p66' homodimer precursor. Since the ribonuclease H (RH) domain contains an occult cleavage site located near its center, cleavage must occur either prior to folding or subsequent to unfolding. Recent NMR studies have identified a slow, subunit-specific RH domain unfolding process proposed to result from a residue tug-of-war between the polymerase and RH domains on the functionally inactive, p66' subunit. Here, we describe a structural comparison of the isolated RH domain with a domain swapped RH dimer that reveals several intrinsically destabilizing characteristics of the isolated domain that facilitate excursions of Tyr427 from its binding pocket and separation of helices B and D. These studies provide independent support for the subunit-selective RH domain unfolding pathway in which instability of the Tyr427 binding pocket facilitates its release followed by domain transfer, acting as a trigger for further RH domain destabilization and subsequent unfolding. As further support for this pathway, NMR studies demonstrate that addition of an RH active site-directed isoquinolone ligand retards the subunit-selective RH' domain unfolding behavior of the p66/p66' homodimer. As a result, this study demonstrates the feasibility of directly targeting RT maturation with therapeutics.


Human Immunodeficiency Virus Reverse Transcriptase

Human Immunodeficiency Virus Reverse Transcriptase

Author: Stuart LeGrice

Publisher: Springer Science & Business Media

Published: 2013-07-23

Total Pages: 358

ISBN-13: 1461472911

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The Reverse Transcriptase (RT) of Human Immunodeficiency Virus Type 1 (HIV-1) arguably ranks amongst one of the most extensively studied retroviral enzymes. Heterologous expression and purification of HIV-1 RT in the early eighties, approval of the first nucleoside analogue RT inhibitor (NRTI) in 1987, discovery of resistance to RT inhibitors, approval of the first non-nucleoside analogue RT inhibitor (NNRTI) in 1996 and the various crystal structures of RT with and without bound substrate(s) and/or inhibitors represent only a few of the important milestones that describe the a bench-to-bedside success in the continuing effort to combat HIV-1 infection and its consequences. Nucleoside and nonnucleoside RT inhibitors remain important components in frequently used drug regimens to treat the infection. RT inhibitors also play important roles in recently validated strategies to prevent transmission of the virus. The relevance of HIV-1 RT as a drug target has simultaneously triggered interest in basic research studies aimed at providing a more detailed understanding of interactions between proteins, nucleic acids, and small molecule ligands in general terms. In light of the ever-growing knowledge on structure and function of HIV-1 RT, this enzyme serves as a valuable “model system” in efforts to develop novel experimental tools and to explain biochemical processes. This monograph is designed to provide an overview of important aspects in past and current HIV-1 RT research, with focus on mechanistic aspects and translation of knowledge into drug discovery and development. The first section includes chapters with emphasis placed on the coordination of the RT-associated DNA polymerase and ribonuclease H (RNase H) activities. The second covers mechanisms of action and future perspectives associated with NRTIs and NNRTIs, while the third section includes chapters focusing on novel strategies to target the RT enzyme. Chapters of the final part are intended to discuss mechanisms involved in HIV variability and the development of drug resistance. We hope that these contributions will stimulate interest, and encourage research aimed at the development of novel RT inhibitors. The lack of bona fide RNase H inhibitors with potent antiviral activity provides an example for challenges and opportunities in the field.


Handbook of Single-Molecule Biophysics

Handbook of Single-Molecule Biophysics

Author: Peter Hinterdorfer

Publisher: Springer Science & Business Media

Published: 2009-12-24

Total Pages: 634

ISBN-13: 0387764976

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This handbook describes experimental techniques to monitor and manipulate individual biomolecules, including fluorescence detection, atomic force microscopy, and optical and magnetic trapping. It includes single-molecule studies of physical properties of biomolecules such as folding, polymer physics of protein and DNA, enzymology and biochemistry, single molecules in the membrane, and single-molecule techniques in living cells.


Desk Encyclopedia of Microbiology

Desk Encyclopedia of Microbiology

Author: Moselio Schaechter

Publisher: Academic Press

Published: 2010-04-19

Total Pages: 1277

ISBN-13: 0080961282

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The Desk Encyclopedia of Microbiology, Second Edition is a single-volume comprehensive guide to microbiology for the advanced reader. Derived from the six volume e-only Encyclopedia of Microbiology, Third Edition, it bridges the gap between introductory texts and specialized reviews. Covering topics ranging from the basic science of microbiology to the current "hot" topics in the field, it will be invaluable for obtaining background information on a broad range of microbiological topics, preparing lectures and preparing grant applications and reports. The most comprehensive single-volume source providing an overview of microbiology to non-specialists Bridges the gap between introductory texts and specialized reviews Provides concise and general overviews of important topics within the field making it a helpful resource when preparing for lectures, writing reports, or drafting grant applications


Histochemistry of Single Molecules

Histochemistry of Single Molecules

Author: Carlo Pellicciari

Publisher: Springer Nature

Published: 2022-09-24

Total Pages: 351

ISBN-13: 1071626752

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This volume details histochemical techniques for the detection of specific molecules or metabolic processes, both at light and electron microscopy. Chapters are divided into seven sections covering Vital histochemistry, Carbohydrate histochemistry, Protein histochemistry, Lipid histochemistry, Nuclear histochemistry, Plant histochemistry and Histochemistry for Nanoscience. Written in the successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible protocols, and notes on troubleshooting and avoiding known pitfalls. The volume also contains three discursive chapters on Histochemistry in advanced cytometry, Lectins and Detection of molecules in plant cell walls by fluorescence microscopy. Authoritative and cutting-edge, Histochemistry of Single Molecules: Methods and Protocols, Second Edition aims to be a useful practical guide for researchers to help further their study in this field.