Crystal structure of human CD38 extracellular domain

Area of Science:

• Biochemistry
• Structural Biology
• Immunology

Background:

• Human CD38 is a multifunctional protein with enzymatic and antigenic roles.
• It synthesizes calcium messengers (cADPR, NAADP) and regulates cell functions.
• CD38 is a marker for HIV-1 infection progression and a negative prognostic indicator for B-cell chronic lymphocytic leukemia (B-CLL).

Purpose of the Study:

• To determine the crystal structure of the soluble extracellular domain of human CD38.
• To elucidate the structural basis for CD38's multifunctionality.

Main Methods:

• X-ray crystallography was used to determine the crystal structure of human CD38 at 1.9 Å resolution.
• Analysis of substrate binding models.

Main Results:

• The crystal structure revealed an overall topology similar to related proteins, with significant changes at the termini.
• The N-terminus shows lateral associations with other CD38 molecules.
• Identification of two key residues potentially controlling CD38's enzymatic activities (NAD hydrolysis, ADP-ribosyl cyclase, cADPR hydrolysis).

Conclusions:

• The determined structure provides insights into CD38's molecular organization.
• Key residues identified may be crucial for modulating CD38's diverse enzymatic functions.
• Structural information can inform therapeutic strategies targeting CD38 in diseases like HIV and B-CLL.