Crystal structure of the APOBEC3G catalytic domain reveals potential oligomerization interfaces.
APOBEC3G is a DNA cytidine deaminase that has antiviral activity against HIV-1 and other pathogenic viruses. In this study the crystal structure of the catalytically active C-terminal domain was determined to 2.25 A. This structure corroborates features previously observed in nuclear magnetic resonance (NMR) studies, a bulge in the second beta strand and a lengthening of the second alpha helix. Oligomerization is postulated to be critical for the function of APOBEC3G. In this structure, four extensive intermolecular interfaces are observed, suggesting potential models for APOBEC3G oligomerization. The structural and functional significance of these interfaces was probed by solution NMR and disruptive variants were designed and tested for DNA deaminase and anti-HIV activities. The variant designed to disrupt the most extensive interface lost both activities. NMR solution data provides evidence that another interface, which coordinates a novel zinc site, also exists. Thus, the observed crystallographic interfaces of APOBEC3G may be important for both oligomerization and function.
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Shivender M D
SM
Shandilya
Madhavi N L
MN
Nalam
Ellen A
EA
Nalivaika
Phillip J
PJ
Gross
Johnathan C
JC
Valesano
Keisuke
K
Shindo
Ming
M
Li
Mary
M
Munson
William E
WE
Royer
Elena
E
Harjes
Takahide
T
Kono
Hiroshi
H
Matsuo
Reuben S
RS
Harris
Mohan
M
Somasundaran
Celia A
CA
Schiffer
D000071480:APOBEC-3G Deaminase; D000595:Amino Acid Sequence; D020134:Catalytic Domain; D003564:Cytidine Deaminase / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D020836:Protein Structure, Quaternary; D016415:Sequence Alignment
D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase