| Structural highlights
Disease
[A1AT_HUMAN] Defects in SERPINA1 are the cause of alpha-1-antitrypsin deficiency (A1ATD) [MIM:613490]. A disorder whose most common manifestation is emphysema, which becomes evident by the third to fourth decade. A less common manifestation of the deficiency is liver disease, which occurs in children and adults, and may result in cirrhosis and liver failure. Environmental factors, particularly cigarette smoking, greatly increase the risk of emphysema at an earlier age.[1] [2] [3]
Function
[A1AT_HUMAN] Inhibitor of serine proteases. Its primary target is elastase, but it also has a moderate affinity for plasmin and thrombin. Irreversibly inhibits trypsin, chymotrypsin and plasminogen activator. The aberrant form inhibits insulin-induced NO synthesis in platelets, decreases coagulation time and has proteolytic activity against insulin and plasmin.[:][4] [5] Short peptide from AAT: reversible chymotrypsin inhibitor. It also inhibits elastase, but not trypsin. Its major physiological function is the protection of the lower respiratory tract against proteolytic destruction by human leukocyte elastase (HLE).[:][6] [7]
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
Serpin (serine protease inhibitor) proteins are involved in diverse physiological processes including inflammation, coagulation, matrix remodeling, and cell differentiation. Deficiency of normal serpin functions leads to various hereditary diseases. Besides their clinical importance, serpin proteins draw much attention due to the large conformational changes that occur upon interaction with proteases. We present here the crystal structure of an uncleaved alpha(1)-antitrypsin determined by the multiple isomorphous replacement method and refined to 2.1 A resolution. The structure, which is the first active serpin structure based on experimental phases, reveals novel conformations in the flexible loops, including the proximal hinge region of the reactive center loop and the surface cavity region in the central beta-sheet, sheet A. The determined loop conformation explains the results of recent mutagenesis studies and provides detailed insights into the protease inhibition mechanism. The high-resolution structure of active alpha(1)-antitrypsin also provides evidence for the existence of localized van-der-Waals strain in the central hydrophobic core.
A 2.1 A resolution structure of an uncleaved alpha(1)-antitrypsin shows variability of the reactive center and other loops.,Kim S, Woo J, Seo EJ, Yu M, Ryu S J Mol Biol. 2001 Feb 9;306(1):109-19. PMID:11178897[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Seyama K, Nukiwa T, Takabe K, Takahashi H, Miyake K, Kira S. Siiyama (serine 53 (TCC) to phenylalanine 53 (TTC)). A new alpha 1-antitrypsin-deficient variant with mutation on a predicted conserved residue of the serpin backbone. J Biol Chem. 1991 Jul 5;266(19):12627-32. PMID:1905728
- ↑ Holmes MD, Brantly ML, Fells GA, Crystal RG. Alpha 1-antitrypsin Wbethesda: molecular basis of an unusual alpha 1-antitrypsin deficiency variant. Biochem Biophys Res Commun. 1990 Aug 16;170(3):1013-20. PMID:2390072
- ↑ Graham A, Kalsheker NA, Bamforth FJ, Newton CR, Markham AF. Molecular characterisation of two alpha-1-antitrypsin deficiency variants: proteinase inhibitor (Pi) Null(Newport) (Gly115----Ser) and (Pi) Z Wrexham (Ser-19----Leu). Hum Genet. 1990 Oct;85(5):537-40. PMID:2227940
- ↑ Tanaka N, Sekiya S, Takamizawa H, Kato N, Moriyama Y, Fujimura S. Characterization of a 54 kDa, alpha 1-antitrypsin-like protein isolated from ascitic fluid of an endometrial cancer patient. Jpn J Cancer Res. 1991 Jun;82(6):693-700. PMID:1906855
- ↑ Niemann MA, Narkates AJ, Miller EJ. Isolation and serine protease inhibitory activity of the 44-residue, C-terminal fragment of alpha 1-antitrypsin from human placenta. Matrix. 1992 Jun;12(3):233-41. PMID:1406456
- ↑ Tanaka N, Sekiya S, Takamizawa H, Kato N, Moriyama Y, Fujimura S. Characterization of a 54 kDa, alpha 1-antitrypsin-like protein isolated from ascitic fluid of an endometrial cancer patient. Jpn J Cancer Res. 1991 Jun;82(6):693-700. PMID:1906855
- ↑ Niemann MA, Narkates AJ, Miller EJ. Isolation and serine protease inhibitory activity of the 44-residue, C-terminal fragment of alpha 1-antitrypsin from human placenta. Matrix. 1992 Jun;12(3):233-41. PMID:1406456
- ↑ Kim S, Woo J, Seo EJ, Yu M, Ryu S. A 2.1 A resolution structure of an uncleaved alpha(1)-antitrypsin shows variability of the reactive center and other loops. J Mol Biol. 2001 Feb 9;306(1):109-19. PMID:11178897 doi:10.1006/jmbi.2000.4357
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