2HCT

Acidic residues at the active sites of CD38 and ADP-ribosyl cyclase determine NAAPD synthesis and hydrolysis activities


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.195 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Acidic residues at the active sites of CD38 and ADP-ribosyl cyclase determine nicotinic acid adenine dinucleotide phosphate (NAADP) synthesis and hydrolysis activities.

Graeff, R.Liu, Q.Kriksunov, I.A.Hao, Q.Lee, H.C.

(2006) J.Biol.Chem. 281: 28951-28957

  • DOI: 10.1074/jbc.M604370200

  • PubMed Abstract: 
  • Nicotinic acid adenine dinucleotide phosphate (NAADP) is a novel metabolite of NADP that has now been established as a Ca(2+) messenger in many cellular systems. Its synthesis is catalyzed by multifunctional enzymes, CD38 and ADP-ribosyl cyclase (cyc ...

    Nicotinic acid adenine dinucleotide phosphate (NAADP) is a novel metabolite of NADP that has now been established as a Ca(2+) messenger in many cellular systems. Its synthesis is catalyzed by multifunctional enzymes, CD38 and ADP-ribosyl cyclase (cyclase). The degradation pathway for NAADP is unknown and no enzyme that can specifically hydrolyze it has yet been identified. Here we show that CD38 can, in fact, hydrolyze NAADP to ADP-ribose 2'-phosphate. This activity was low at neutrality but greatly increased at acidic pH. This novel pH dependence suggests that the hydrolysis is determined by acidic residues at the active site. X-ray crystallography of the complex of CD38 with one of its substrates, NMN, showed that the nicotinamide moiety was in close contact with Glu(146) at 3.27 A and Asp(155) at 2.52 A. Changing Glu(146) to uncharged Gly and Ala, and Asp(155) to Gln and Asn, by site-directed mutagenesis indeed eliminated the strong pH dependence. Changing Asp(155) to Glu, in contrast, preserved the dependence. The specificity of the two acidic residues was further demonstrated by changing the adjacent Asp(147) to Val, which had minimal effect on the pH dependence. Crystallography confirmed that Asp(147) was situated and directed away from the bound substrate. Synthesis of NAADP catalyzed by CD38 is known to have strong preference for acidic pH, suggesting that Glu(146) and Asp(155) are also critical determinants. This was shown to be case by mutagensis. Likewise, using similar approaches, Glu(98) of the cyclase, which is equivalent to Glu(146) in CD38, was found to be responsible for controlling the pH dependence of NAADP synthesis by the cyclase. Based on these findings, a catalytic model is proposed.


    Organizational Affiliation

    Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ADP-ribosyl cyclase 1
A, B
262Homo sapiensMutation(s): 7 
Gene Names: CD38
EC: 3.2.2.6
Find proteins for P28907 (Homo sapiens)
Go to Gene View: CD38
Go to UniProtKB:  P28907
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NMN
Query on NMN

Download SDF File 
Download CCD File 
A, B
BETA-NICOTINAMIDE RIBOSE MONOPHOSPHATE
NICOTINAMIDE MONONUCLEOTIDE
C11 H16 N2 O8 P
DAYLJWODMCOQEW-TURQNECASA-O
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.195 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 41.715α = 106.26
b = 52.823β = 91.85
c = 65.578γ = 95.25
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data scaling
MOLREPphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-08-22
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Version format compliance