| Structural highlights
1yuo is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Gene: | UNG (Homo sapiens) |
| Activity: | Uridine nucleosidase, with EC number 3.2.2.3 |
| Resources: | FirstGlance, OCA, RCSB, PDBsum |
Disease
[UNG_HUMAN] Defects in UNG are a cause of immunodeficiency with hyper-IgM type 5 (HIGM5) [MIM:608106]. A rare immunodeficiency syndrome characterized by normal or elevated serum IgM levels with absence of IgG, IgA, and IgE. It results in a profound susceptibility to bacterial infections.[1] [2]
Function
[UNG_HUMAN] Excises uracil residues from the DNA which can arise as a result of misincorporation of dUMP residues by DNA polymerase or due to deamination of cytosine.
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
Cold-adapted enzymes are characterised by an increased catalytic efficiency and reduced temperature stability compared to their mesophilic counterparts. Lately, it has been suggested that an optimisation of the electrostatic surface potential is a strategy for cold adaptation for some enzymes. A visualisation of the electrostatic surface potential of cold-adapted uracil-DNA N-glycosylase (cUNG) from Atlantic cod indicates a more positively charged surface near the active site compared to human UNG (hUNG). In order to investigate the importance of the altered surface potential for the cold-adapted features of cod UNG, six mutants have been characterised and compared to cUNG and hUNG. The cUNG quadruple mutant (V171E, K185V, H250Q and H275Y) and four corresponding single mutants all comprise substitutions of residues present in the human enzyme. A human UNG mutant, E171V, comprises the equivalent residue found in cod UNG. In addition, crystal structures of the single mutants V171E and E171V have been determined. Results from the study show that a more negative electrostatic surface potential reduces the activity and increases the stability of cod UNG, and suggest an optimisation of the surface potential as a strategy for cold-adaptation of this enzyme. Val171 in cod UNG is especially important in this respect.
Optimisation of the surface electrostatics as a strategy for cold adaptation of uracil-DNA N-glycosylase (UNG) from Atlantic cod (Gadus morhua).,Moe E, Leiros I, Riise EK, Olufsen M, Lanes O, Smalas A, Willassen NP J Mol Biol. 2004 Nov 5;343(5):1221-30. PMID:15491608[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Imai K, Slupphaug G, Lee WI, Revy P, Nonoyama S, Catalan N, Yel L, Forveille M, Kavli B, Krokan HE, Ochs HD, Fischer A, Durandy A. Human uracil-DNA glycosylase deficiency associated with profoundly impaired immunoglobulin class-switch recombination. Nat Immunol. 2003 Oct;4(10):1023-8. Epub 2003 Sep 7. PMID:12958596 doi:http://dx.doi.org/10.1038/ni974
- ↑ Kavli B, Andersen S, Otterlei M, Liabakk NB, Imai K, Fischer A, Durandy A, Krokan HE, Slupphaug G. B cells from hyper-IgM patients carrying UNG mutations lack ability to remove uracil from ssDNA and have elevated genomic uracil. J Exp Med. 2005 Jun 20;201(12):2011-21. PMID:15967827 doi:10.1084/jem.20050042
- ↑ Moe E, Leiros I, Riise EK, Olufsen M, Lanes O, Smalas A, Willassen NP. Optimisation of the surface electrostatics as a strategy for cold adaptation of uracil-DNA N-glycosylase (UNG) from Atlantic cod (Gadus morhua). J Mol Biol. 2004 Nov 5;343(5):1221-30. PMID:15491608 doi:10.1016/j.jmb.2004.09.004
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