Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Reversible and Irreversible Processes01:14

Reversible and Irreversible Processes

5.8K
The thermodynamic processes can be classified into reversible and irreversible processes. The processes that can be restored to their initial state are called reversible processes. It is only possible if the process is in quasi-static equilibrium, i.e., it takes place in infinitesimally small steps, and the system remains at equilibrium However, these are ideal processes and do not occur naturally. An ideal system undergoing a reversible process is always in thermodynamic equilibrium within...
5.8K
Diode: Reverse bias01:14

Diode: Reverse bias

1.9K
A diode is reverse-biased when the positive terminal of an external voltage source is connected to the n-type material and the negative terminal to the p-type material. This configuration opposes the natural direction of current flow through the diode, effectively increasing the width of the depletion region and the barrier potential. The reverse bias condition produces a minimal leakage current, primarily due to minority charge carriers. This leakage becomes significant when the reverse...
1.9K
Modeling of Diode Reverse Characteristics01:14

Modeling of Diode Reverse Characteristics

619
In electronic circuits, reverse-biased diode configurations are critical for regulating voltage levels. Zener diodes exploit the reverse breakdown phenomenon and exhibit a controlled breakdown at a specific Zener voltage (VZ). They are designed to maintain a constant voltage across their terminals and are commonly used for voltage regulation in circuits.
When a reverse voltage applied to a Zener diode exceeds its breakdown voltage, the diode enters the breakdown region. At this point, the...
619
Entropy Change in Reversible Processes01:10

Entropy Change in Reversible Processes

3.2K
In the Carnot engine, which achieves the maximum efficiency between two reservoirs of fixed temperatures, the total change in entropy is zero. The observation can be generalized by considering any reversible cyclic process consisting of many Carnot cycles. Thus, it can be stated that the total entropy change of any ideal reversible cycle is zero.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
3.2K
Viral Mutations00:36

Viral Mutations

39.9K
A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material...
39.9K
SN1 Reaction: Stereochemistry02:15

SN1 Reaction: Stereochemistry

10.3K
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
10.3K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Microbiome-generated antifolates.

FEBS letters·2026
Same author

The aminosalicylate - folate connection.

Drug metabolism reviews·2024
Same author

Targeting the Structural Maturation Pathway of HIV-1 Reverse Transcriptase.

Biomolecules·2023
Same author

Mechanism by which T7 bacteriophage protein Gp1.2 inhibits <i>Escherichia coli</i> dGTPase.

Proceedings of the National Academy of Sciences of the United States of America·2022
Same author

Species variations in XRCC1 recruitment strategies for FHA domain-containing proteins.

DNA repair·2022
Same author

Response to Letter to the Editor regarding "Comparison of phytochemical composition of Ginkgo biloba extracts using a combination of non-targeted and targeted analytical approaches".

Analytical and bioanalytical chemistry·2021

Related Experiment Video

Updated: Jan 30, 2026

Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors
05:46

Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors

Published on: April 9, 2014

18.4K

HIV-1 Reverse Transcriptase: A Metamorphic Protein with Three Stable States.

Robert E London1

  • 1Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.

Structure (London, England : 1993)
|January 15, 2019
PubMed
Summary
This summary is machine-generated.

Metamorphic proteins can adopt multiple stable structures. HIV-1 reverse transcriptase uses this ability, with its polymerase domains alternatively folding to form a functional heterodimer.

Keywords:
HIV-1 reverse transcriptasemetamorphic proteinmetamorphic transitionprogrammed unfoldingsubunit-specific RH-domain unfolding

More Related Videos

Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays
13:58

Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays

Published on: September 26, 2011

32.2K
Author Spotlight: Exploring the Role of Unfolded Protein Response in HIV-1 Replication and Infectivity
10:12

Author Spotlight: Exploring the Role of Unfolded Protein Response in HIV-1 Replication and Infectivity

Published on: June 14, 2024

2.6K

Related Experiment Videos

Last Updated: Jan 30, 2026

Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors
05:46

Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors

Published on: April 9, 2014

18.4K
Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays
13:58

Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays

Published on: September 26, 2011

32.2K
Author Spotlight: Exploring the Role of Unfolded Protein Response in HIV-1 Replication and Infectivity
10:12

Author Spotlight: Exploring the Role of Unfolded Protein Response in HIV-1 Replication and Infectivity

Published on: June 14, 2024

2.6K

Area of Science:

  • Biochemistry
  • Structural Biology
  • Molecular Biology

Background:

  • Protein sequence-structure relationships can be ambiguous, allowing single sequences to adopt alternative folds.
  • Metamorphic proteins exploit this ambiguity for diverse biological functions.
  • HIV-1 reverse transcriptase is an early example of a metamorphic protein with functional implications.

Purpose of the Study:

  • To investigate the structural basis of protein metamorphosis in HIV-1 reverse transcriptase.
  • To understand the factors driving the alternative folding of polymerase domains.
  • To elucidate the programmed unfolding mechanism in the ribonuclease H domain.

Main Methods:

  • Structural characterization of the p66 precursor protein.
  • Nuclear Magnetic Resonance (NMR) spectroscopy.
  • Molecular modeling studies.

Main Results:

  • Identified alternative stable folds for protein sequences.
  • Characterized the structure of the HIV-1 reverse transcriptase p66 precursor.
  • Provided insights into the metamorphic transition and subunit-specific unfolding.

Conclusions:

  • HIV-1 reverse transcriptase's functional heterodimer contains two alternatively folded polymerase domains.
  • A programmed unfolding step is crucial for converting the p66/p66' precursor to the mature p66/p51 heterodimer.
  • Understanding protein metamorphosis offers insights into protein function and evolution.