Related Experiment Video

Updated: Jun 19, 2026

Use of Stopped-Flow Fluorescence and Labeled Nucleotides to Analyze the ATP Turnover Cycle of Kinesins
07:25

Use of Stopped-Flow Fluorescence and Labeled Nucleotides to Analyze the ATP Turnover Cycle of Kinesins

Published on: October 17, 2014

An allosteric transition trapped in an intermediate state of a new kinesin-inhibitor complex

Hung Yi Kristal Kaan1, Venkatasubramanian Ulaganathan, David D Hackney

  • 1The Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, Scotland, UK.

The Biochemical Journal
|October 2, 2009
PubMed

Insights

Human kinesin Eg5 is a cancer drug target. We determined the crystal structure of Eg5 bound to STLC, revealing distinct inhibitor-bound and intermediate states, clarifying drug-induced conformational changes.

Area of Science:

  • Structural Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Human kinesin Eg5 is crucial for mitosis, involved in centrosome separation and bipolar spindle formation.
  • Eg5 is a validated target for cancer chemotherapy, with multiple inhibitors in clinical trials.

Purpose of the Study:

  • To elucidate the structural mechanism of Eg5 inhibition by STLC.
  • To provide atomic-level insights into the conformational changes induced by Eg5 inhibitors.

Main Methods:

  • X-ray crystallography of the Eg5 motor domain complexed with STLC.
  • Analysis of distinct molecular conformations within the crystal structure.

Main Results:

  • The crystal structure of the Eg5-STLC complex was determined at 2.0 Å resolution.
  • Two Eg5 molecules showed a final inhibitor-bound state with loop L5 closure, helix α4 rotation, and neck-linker docking.
  • A third Eg5 molecule revealed an intermediate state, demonstrating localized binding pocket changes without propagated structural alterations.

Conclusions:

  • The study provides the first structural evidence of an intermediate state in Eg5 inhibition.
  • This reveals the sequential nature of drug-induced conformational changes in Eg5.
  • Understanding these conformational dynamics aids in the rational design of novel Eg5-targeting cancer therapeutics.

More Related Videos

Assembling Molecular Shuttles Powered by Reversibly Attached Kinesins08:04

Assembling Molecular Shuttles Powered by Reversibly Attached Kinesins

Published on: January 26, 2019

A Semi-High-Throughput Adaptation of the NADH-Coupled ATPase Assay for Screening Small Molecule Inhibitors10:28

A Semi-High-Throughput Adaptation of the NADH-Coupled ATPase Assay for Screening Small Molecule Inhibitors

Published on: August 17, 2019

Related Concept Videos

Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Allosteric Regulation01:08

Allosteric Regulation

Allosteric regulation of enzymes occurs when the binding of an effector molecule to a site that is different from the active site causes a change in the enzymatic activity. This alternate site is called an allosteric site, and an enzyme can contain more than one of these sites. Allosteric regulation can either be positive or negative, resulting in an increase or decrease in enzyme activity. Most enzymes that display allosteric regulation are metabolic enzymes involved in the degradation or...
Destabilization of Microtubules01:45

Destabilization of Microtubules

The destabilization of microtubules can occur during different stages of the microtubule lifecycle, such as nucleation or elongation. It can take place at either end of the microtubule or in the microtubule lattices as a whole. The lifespan of individual microtubules within a cell varies according to the cell type and stage of the cell cycle. During interphase, the lifespan of the microtubule is about 30 minutes, while during cell division, it is about 15 minutes. In axonal microtubules of...
ATP Synthase: Mechanism01:48

ATP Synthase: Mechanism

In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased ATP...