GI-ALPHA-1 BOUND TO GDP AND MAGNESIUMGI-ALPHA-1 BOUND TO GDP AND MAGNESIUM

Structural highlights

1bof is a 1 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.2Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

GNAI1_RAT Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. The G(i) proteins are involved in hormonal regulation of adenylate cyclase: they inhibit the cyclase in response to beta-adrenergic stimuli. The inactive GDP-bound form prevents the association of RGS14 with centrosomes and is required for the translocation of RGS14 from the cytoplasm to the plasma membrane. May play a role in cell division.[1]

Evolutionary Conservation

 

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The effect of Mg2+ binding on the conformation of the inactive GDP-bound complex of the heterotrimeric G protein alpha subunit Gi alpha 1 has been investigated by X-ray crystallography. Crystal structures of the Gi alpha 1.GDP complex were determined after titration with 5, 10, 100, and 200 mM Mg2+. Comparison of these structures with that of the Mg2+-free complex revealed Mg2+ bound at the same site as observed in the structure of the active, Gi alpha 1. GTP gamma S.Mg2+-bound complex of Gi alpha 1, with a similar coordination scheme except for the substitution of a water molecule for an oxygen ligand of the gamma-phosphate of Gi alpha 1.GTP gamma S. Mg2+. In contrast to the GDP.Mg2+ complex of Gt alpha and of other G proteins, switch I residues of Gi alpha 1 participate in Mg2+ binding and undergo conformational changes as a consequence of Mg2+ binding. Partial order is induced in switch II, which is disordered in the Mg2+-free complex, but no order is observed in the switch III region. This contrasts with the GDP.Mg2+ complex of Gt alpha in which both switch II and III switch are ordered. Mg2+ binding also induces binding of an SO42- molecule to the active site in a manner which may mimic a Gi alpha 1.GDP.PO42-.Mg2+ product complex. Implications of these findings are discussed.

Crystal structures of the G protein Gi alpha 1 complexed with GDP and Mg2+: a crystallographic titration experiment.,Coleman DE, Sprang SR Biochemistry. 1998 Oct 13;37(41):14376-85. PMID:9772163[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Shu FJ, Ramineni S, Amyot W, Hepler JR. Selective interactions between Gi alpha1 and Gi alpha3 and the GoLoco/GPR domain of RGS14 influence its dynamic subcellular localization. Cell Signal. 2007 Jan;19(1):163-76. Epub 2006 Jul 25. PMID:16870394 doi:http://dx.doi.org/10.1016/j.cellsig.2006.06.002
  2. Coleman DE, Sprang SR. Crystal structures of the G protein Gi alpha 1 complexed with GDP and Mg2+: a crystallographic titration experiment. Biochemistry. 1998 Oct 13;37(41):14376-85. PMID:9772163 doi:10.1021/bi9810306

1bof, resolution 2.20Å

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