7dcb

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The structure of the Arabidopsis thaliana guanosine deaminase complexed with inosineThe structure of the Arabidopsis thaliana guanosine deaminase complexed with inosine

Structural highlights

7dcb is a 2 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

GSDA_ARATH Catalyzes the hydrolytic deamination of guanosine, producing xanthosine and ammonia. Deaminates exclusively guanosine and 2'-deoxyguanosine but no other aminated purines, pyrimidines, or pterines. Deamination of guanosine by GSDA is the only source of xanthosine production in Arabidopsis.[1]

Publication Abstract from PubMed

In plants, guanosine deaminase (GSDA) catalyzes the deamination of guanosine for nitrogen recycling and re-utilization. We previously solved crystal structures of GSDA from Arabidopsis thaliana (AtGSDA) and identified several novel substrates for this enzyme, but the structural basis of the enzyme activation/inhibition is poorly understood. Here, we continued to solve 8 medium-to-high resolution (1.85-2.60 A) cocrystal structures, which involved AtGSDA and its variants bound by a few ligands, and investigated their binding modes through structural studies and thermal shift analysis. Besides the lack of a 2-amino group of these guanosine derivatives, we discovered that AtGSDA's inactivity was due to the its inability to seclude its active site. Furthermore, the C-termini of the enzyme displayed conformational diversities under certain circumstances. The lack of functional amino groups or poor interactions/geometries of the ligands at the active sites to meet the precise binding and activation requirements for deamination both contributed to AtGSDA's inactivity toward the ligands. Altogether, our combined structural and biochemical studies provide insight into GSDA.

Substrate Specificity of GSDA Revealed by Cocrystal Structures and Binding Studies.,Jia Q, Zhang J, Zeng H, Tang J, Xiao N, Gao S, Li H, Xie W Int J Mol Sci. 2022 Nov 29;23(23):14976. doi: 10.3390/ijms232314976. PMID:36499303[2]

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

See Also

References

  1. Dahncke K, Witte CP. Plant purine nucleoside catabolism employs a guanosine deaminase required for the generation of xanthosine in Arabidopsis. Plant Cell. 2013 Oct;25(10):4101-9. doi: 10.1105/tpc.113.117184. Epub 2013 Oct, 15. PMID:24130159 doi:http://dx.doi.org/10.1105/tpc.113.117184
  2. Jia Q, Zhang J, Zeng H, Tang J, Xiao N, Gao S, Li H, Xie W. Substrate Specificity of GSDA Revealed by Cocrystal Structures and Binding Studies. Int J Mol Sci. 2022 Nov 29;23(23):14976. PMID:36499303 doi:10.3390/ijms232314976

7dcb, resolution 2.00Å

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