Related Experiment Video
Updated: Jun 14, 2026

Studying DNA Looping by Single-Molecule FRET
Published on: June 28, 2014
Importance of loop dynamics in the neocarzinostatin chromophore binding and release mechanisms
1Department of Chemistry and the Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA.
Abstract:
Neocarzinostatin (NCS) is an antitumor chromophore carrier protein with many therapeutic applications. To characterize its binding and release mechanism, we have carried out molecular dynamics (MD) simulations for apo-NCS and holo-NCS. Although the beta-sheet regions of the protein exhibit restricted motion, large atomic fluctuations were observed in the loop regions, especially loop 99-104. This loop undergoes a "door-opening" motion that can facilitate chromophore binding and release. Calculated NMR order parameters confirm the simulated loop flexibility. We also provide a proposed explanation for the release rate difference for two mutants F78L and F78A through our simulation. The binding site structures of holo-NCS were also validated by chemical shift perturbations. Based on these results, a new binding and release mechanism for the NCS chromophore is proposed.
Related Concept Videos
Protein-Drug Binding: Mechanism and Kinetics
Various forces drive these interactions, including hydrogen bonds, hydrophobic interactions, ionic bonds, electrostatic interactions, and van der Waals forces. These bonds enable drugs to bind to specific sites on proteins,...
Regulation of Nuclear Protein Sorting
Nucleosome Remodeling
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Cell Signaling Feedback Loops
Negative feedback loops
Most signaling systems have negative feedback loops that can perform different functions such as output limiter, and adaptation.
Output limiter
Upon receiving an input signal, the cellular response rapidly increases until a threshold is reached. Beyond this threshold, a negative feedback loop...
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...

