Related Experiment Video
Updated: Jul 18, 2026

Imaging Initial Ca2+ Microdomains in Primary T Cells
Published on: October 4, 2024
Structural basis for formation and hydrolysis of the calcium messenger cyclic ADP-ribose by human CD38
Qun Liu1, Irina A Kriksunov, Richard Graeff
1MacCHESS, Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853, USA.
Abstract:
Human CD38 is a multifunctional ectoenzyme responsible for catalyzing the conversions from nicotinamide adenine dinucleotide (NAD) to cyclic ADP-ribose (cADPR) and from cADPR to ADP-ribose (ADPR). Both cADPR and ADPR are calcium messengers that can mobilize intracellular stores and activate influx as well. In this study, we determined three crystal structures of the human CD38 enzymatic domain complexed with cADPR at 1.5-A resolution, with its analog, cyclic GDP-ribose (cGDPR) (1.68 A) and with NGD (2.1 A) a substrate analog of NAD. The results indicate that the binding of cADPR or cGDPR to the active site induces structural rearrangements in the dipeptide Glu(146)-Asp(147) by as much as 2.7 A) providing the first direct evidence of a conformational change at the active site during catalysis. In addition, Glu(226) is shown to be critical not only in catalysis but also in positioning of cADPR at the catalytic site through strong hydrogen bonding interactions. Structural details obtained from these complexes provide a step-by-step description of the catalytic processes in the synthesis and hydrolysis of cADPR.
More Related Videos
08:27Expression and Purification of the Human Lipid-sensitive Cation Channel TRPC3 for Structural Determination by Single-particle Cryo-electron Microscopy
Published on: January 7, 2019
11:25Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins
Published on: October 4, 2017
Related Concept Videos
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
IP3/DAG Signaling Pathway
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Amplifying Signals via Second Messengers
Structure of Cadherins
Intracellular Signaling Cascades