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

Stereoisomerism02:52

Stereoisomerism

14.2K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
14.2K
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration02:34

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

9.8K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
9.8K
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

2.6K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.6K
Stereoisomerism of Cyclic Compounds02:33

Stereoisomerism of Cyclic Compounds

11.4K
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
11.4K
Regioselectivity and Stereochemistry of Hydroboration02:36

Regioselectivity and Stereochemistry of Hydroboration

9.6K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
9.6K
E2 Reaction: Stereochemistry and Regiochemistry02:43

E2 Reaction: Stereochemistry and Regiochemistry

14.0K
Elimination reactions of alkyl halides can yield one or more alkenes depending on the specific regiochemical and stereochemical considerations. While the regiochemistry of the reaction governs the location of the double bond in the product, the stereochemical requirements often influence the geometry.
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major...
14.0K

You might also read

Related Articles

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

Sort by
Same author

Lysozyme revisited: evaluating models of a reference protein in structural biology.

Current research in structural biology·2026
Same author

Impact of Single Halogen Atom Substitutions on Antiviral Profile of Inhibitors Targeting SARS-CoV‑2 Main Protease.

ACS omega·2026
Same author

How to mitigate the caveat emptor burden of human and machine users of the Protein Data Bank.

Acta crystallographica. Section D, Structural biology·2026
Same author

A Critical Look at the Crystal Structures of cAMP-Dependent Protein Kinases.

Kinases and phosphatases·2025
Same author

Activity and structure of human (d)CTP deaminase CDADC1.

Proceedings of the National Academy of Sciences of the United States of America·2025
Same author

A Bifunctional Phosphoglucomutase/Phosphomannomutase from <i>Thermococcus kodakarensis</i>: Biophysical Analysis and Cryo-EM Structure.

Biomolecules·2025

Related Experiment Video

Updated: Mar 1, 2026

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
14:55

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy

Published on: September 17, 2017

16.1K

Stereochemistry and Validation of Macromolecular Structures.

Alexander Wlodawer1

  • 1Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, 21702, USA. wlodawer@nih.gov.

Methods in Molecular Biology (Clifton, N.J.)
|June 3, 2017
PubMed
Summary

Macromolecular structure quality is ensured by stereochemical rules. This chapter reviews methods for validating crystallographic and NMR data models against these principles for accurate structural biology.

Keywords:
Bond anglesBond lengthsCrystal structureGeometrical criteriaNMR structureProtein Data Bank (PDB)Quality checkRamachandran plot

More Related Videos

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
14:44

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

Published on: December 16, 2013

10.1K
Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies
10:01

Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies

Published on: November 28, 2017

20.5K

Related Experiment Videos

Last Updated: Mar 1, 2026

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
14:55

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy

Published on: September 17, 2017

16.1K
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
14:44

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

Published on: December 16, 2013

10.1K
Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies
10:01

Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies

Published on: November 28, 2017

20.5K

Area of Science:

  • Structural biology and biochemistry, focusing on macromolecular structures.

Background:

  • Macromolecular structures are fundamentally governed by stereochemical principles.
  • The Protein Data Bank (PDB) archives structural data derived from experimental methods like X-ray crystallography and Nuclear Magnetic Resonance (NMR) spectroscopy.
  • Ensuring the accuracy of these deposited models is crucial for downstream research.

Purpose of the Study:

  • To discuss the stereochemical rules pertinent to macromolecular structures.
  • To summarize practical, computer-based methods and tools for verifying model quality.
  • To highlight the importance of adhering to established structural principles.

Main Methods:

  • Review of established stereochemical rules for macromolecules.
  • Summary of computational tools and validation approaches.
  • Discussion of data interpretation in structural biology.

Main Results:

  • Identification of key stereochemical principles governing macromolecular conformation.
  • Overview of available software and techniques for structural model validation.
  • Emphasis on the practical application of these tools in structural biology workflows.

Conclusions:

  • Adherence to stereochemical rules is essential for reliable macromolecular models.
  • Computer-based validation tools are vital for assessing the quality of PDB data.
  • Rigorous validation ensures the integrity of structural biology research.