| Structural highlights
Disease
[SPYA_HUMAN] Defects in AGXT are the cause of hyperoxaluria primary type 1 (HP1) [MIM:259900]; also known as primary hyperoxaluria type I (PH1) and oxalosis I. HP1 is a rare autosomal recessive inborn error of glyoxylate metabolism characterized by increased excretion of oxalate and glycolate, and the progressive accumulation of insoluble calcium oxalate in the kidney and urinary tract.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]
Publication Abstract from PubMed
The alanine:glyoxylate aminotransferase (AGT), a hepatocyte-specific pyridoxal-5'-phosphate (PLP) dependent enzyme, transaminates L-alanine and glyoxylate to glycine and pyruvate, thus detoxifying glyoxylate and preventing pathological oxalate precipitation in tissues. In the widely accepted catalytic mechanism of the aminotransferase family, the lysine binding to PLP acts as a catalyst in the stepwise 1,3-proton transfer, interconverting the external aldimine to ketimine. This step requires protonation by a conserved aspartate of the pyridine nitrogen of PLP to enhance its ability to stabilize the carbanionic intermediate. The aspartate residue is also responsible for a significant geometrical distortion of the internal aldimine, crucial for catalysis. We present the structure of human AGT in which complete X-ray photoreduction of the Schiff base has occurred. This result, together with two crystal structures of the conserved aspartate pathogenic variant (D183N) and the molecular modeling of the transaldimination step, led us to propose that an interplay of opposite forces, which we named spring mechanism, finely tunes PLP geometry during catalysis and is essential to move the external aldimine in the correct position in order for the 1,3-proton transfer to occur.
Radiation damage at the active site of human alanine:glyoxylate aminotransferase reveals that the cofactor position is finely tuned during catalysis.,Giardina G, Paiardini A, Montioli R, Cellini B, Voltattorni CB, Cutruzzola F Sci Rep. 2017 Sep 15;7(1):11704. doi: 10.1038/s41598-017-11948-w. PMID:28916765[19]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Purdue PE, Takada Y, Danpure CJ. Identification of mutations associated with peroxisome-to-mitochondrion mistargeting of alanine/glyoxylate aminotransferase in primary hyperoxaluria type 1. J Cell Biol. 1990 Dec;111(6 Pt 1):2341-51. PMID:1703535
- ↑ Nishiyama K, Funai T, Katafuchi R, Hattori F, Onoyama K, Ichiyama A. Primary hyperoxaluria type I due to a point mutation of T to C in the coding region of the serine:pyruvate aminotransferase gene. Biochem Biophys Res Commun. 1991 May 15;176(3):1093-9. PMID:2039493
- ↑ Purdue PE, Lumb MJ, Allsop J, Minatogawa Y, Danpure CJ. A glycine-to-glutamate substitution abolishes alanine:glyoxylate aminotransferase catalytic activity in a subset of patients with primary hyperoxaluria type 1. Genomics. 1992 May;13(1):215-8. PMID:1349575
- ↑ Minatogawa Y, Tone S, Allsop J, Purdue PE, Takada Y, Danpur CJ, Kido R. A serine-to-phenylalanine substitution leads to loss of alanine:glyoxylate aminotransferase catalytic activity and immunoreactivity in a patient with primary hyperoxaluria type 1. Hum Mol Genet. 1992 Nov;1(8):643-4. PMID:1301173
- ↑ Danpure CJ, Purdue PE, Fryer P, Griffiths S, Allsop J, Lumb MJ, Guttridge KM, Jennings PR, Scheinman JI, Mauer SM, et al.. Enzymological and mutational analysis of a complex primary hyperoxaluria type 1 phenotype involving alanine:glyoxylate aminotransferase peroxisome-to-mitochondrion mistargeting and intraperoxisomal aggregation. Am J Hum Genet. 1993 Aug;53(2):417-32. PMID:8101040
- ↑ von Schnakenburg C, Rumsby G. Primary hyperoxaluria type 1: a cluster of new mutations in exon 7 of the AGXT gene. J Med Genet. 1997 Jun;34(6):489-92. PMID:9192270
- ↑ von Schnakenburg C, Rumsby G. Identification of new mutations in primary hyperoxaluria type 1 (PH1). J Nephrol. 1998 Mar-Apr;11 Suppl 1:15-7. PMID:9604803
- ↑ Amoroso A, Pirulli D, Puzzer D, Ferri L, Crovella S, Ferrettini C, Marangella M, Mazzola G, Florian F. Gene symbol: AGXT. Disease: primary hyperoxaluria type I. Hum Genet. 1999 May;104(5):441. PMID:10394939
- ↑ Pirulli D, Puzzer D, Ferri L, Crovella S, Amoroso A, Ferrettini C, Marangella M, Mazzola G, Florian F. Molecular analysis of hyperoxaluria type 1 in Italian patients reveals eight new mutations in the alanine: glyoxylate aminotransferase gene. Hum Genet. 1999 Jun;104(6):523-5. PMID:10453743
- ↑ Rinat C, Wanders RJ, Drukker A, Halle D, Frishberg Y. Primary hyperoxaluria type I: a model for multiple mutations in a monogenic disease within a distinct ethnic group. J Am Soc Nephrol. 1999 Nov;10(11):2352-8. PMID:10541294
- ↑ Basmaison O, Rolland MO, Cochat P, Bozon D. Identification of 5 novel mutations in the AGXT gene. Hum Mutat. 2000 Jun;15(6):577. PMID:10862087 doi:<577::AID-HUMU9>3.0.CO;2-# 10.1002/1098-1004(200006)15:6<577::AID-HUMU9>3.0.CO;2-#
- ↑ Lumb MJ, Danpure CJ. Functional synergism between the most common polymorphism in human alanine:glyoxylate aminotransferase and four of the most common disease-causing mutations. J Biol Chem. 2000 Nov 17;275(46):36415-22. PMID:10960483 doi:10.1074/jbc.M006693200
- ↑ Coulter-Mackie MB, Tung A, Henderson HE, Toone JR, Applegarth DA. The AGT gene in Africa: a distinctive minor allele haplotype, a polymorphism (V326I), and a novel PH1 mutation (A112D) in Black Africans. Mol Genet Metab. 2003 Jan;78(1):44-50. PMID:12559847
- ↑ Santana A, Salido E, Torres A, Shapiro LJ. Primary hyperoxaluria type 1 in the Canary Islands: a conformational disease due to I244T mutation in the P11L-containing alanine:glyoxylate aminotransferase. Proc Natl Acad Sci U S A. 2003 Jun 10;100(12):7277-82. Epub 2003 May 30. PMID:12777626 doi:10.1073/pnas.1131968100
- ↑ van Woerden CS, Groothoff JW, Wijburg FA, Annink C, Wanders RJ, Waterham HR. Clinical implications of mutation analysis in primary hyperoxaluria type 1. Kidney Int. 2004 Aug;66(2):746-52. PMID:15253729 doi:10.1111/j.1523-1755.2004.00796.x
- ↑ Monico CG, Olson JB, Milliner DS. Implications of genotype and enzyme phenotype in pyridoxine response of patients with type I primary hyperoxaluria. Am J Nephrol. 2005 Mar-Apr;25(2):183-8. Epub 2005 Apr 21. PMID:15849466 doi:10.1159/000085411
- ↑ Frishberg Y, Rinat C, Shalata A, Khatib I, Feinstein S, Becker-Cohen R, Weismann I, Wanders RJ, Rumsby G, Roels F, Mandel H. Intra-familial clinical heterogeneity: absence of genotype-phenotype correlation in primary hyperoxaluria type 1 in Israel. Am J Nephrol. 2005 May-Jun;25(3):269-75. Epub 2005 Jun 15. PMID:15961946 doi:10.1159/000086357
- ↑ Coulter-Mackie MB, Lian Q, Applegarth D, Toone J. The major allele of the alanine:glyoxylate aminotransferase gene: nine novel mutations and polymorphisms associated with primary hyperoxaluria type 1. Mol Genet Metab. 2005 Sep-Oct;86(1-2):172-8. Epub 2005 Jun 15. PMID:15963748 doi:10.1016/j.ymgme.2005.05.005
- ↑ Giardina G, Paiardini A, Montioli R, Cellini B, Voltattorni CB, Cutruzzola F. Radiation damage at the active site of human alanine:glyoxylate aminotransferase reveals that the cofactor position is finely tuned during catalysis. Sci Rep. 2017 Sep 15;7(1):11704. doi: 10.1038/s41598-017-11948-w. PMID:28916765 doi:http://dx.doi.org/10.1038/s41598-017-11948-w
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