4QG1: Crystal Structure Of The Tetrameric Gtp/datp-bound Samhd1 (rn206) Mutant Catalytic Core

Citation:
Abstract
Sterile alpha motif and histidine-aspartate domain-containing protein 1 (SAMHD1) plays a critical role in inhibiting HIV infection, curtailing the pool of dNTPs available for reverse transcription of the viral genome. Recent structural data suggested a compelling mechanism for the regulation of SAMHD1 enzymatic activity and revealed dGTP-induced association of two inactive dimers into an active tetrameric enzyme. Here, we present the crystal structures of SAMHD1 catalytic core (residues 113-626) tetramers, complexed with mixtures of nucleotides, including dGTP/dATP, dGTP/dCTP, dGTP/dTTP, and dGTP/dUTP. The combined structural and biochemical data provide insight into dNTP promiscuity at the secondary allosteric site and how enzymatic activity is modulated. In addition, we present biochemical analyses of GTP-induced SAMHD1 full-length tetramerization and the structure of SAMHD1 catalytic core tetramer in complex with GTP/dATP, revealing the structural basis of GTP-mediated SAMHD1 activation. Altogether, the data presented here advance our understanding of SAMHD1 function during cellular homeostasis.
PDB ID: 4QG1Download
MMDB ID: 123846
PDB Deposition Date: 2014/5/22
Updated in MMDB: 2014/12
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Similar Structures:
Biological Unit for 4QG1: tetrameric; determined by author and by software (PISA)
Molecular Components in 4QG1
Label Count Molecule
Proteins (4 molecules)
4
Deoxynucleoside Triphosphate Triphosphohydrolase Samhd1(Gene symbol: SAMHD1)
Molecule annotation
Chemicals (16 molecules)
1
8
2
4
3
4
* Click molecule labels to explore molecular sequence information.

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