| 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]
Publication Abstract from PubMed
alpha(1)-Antitrypsin (alpha1AT) deficiency is a disease with multiple manifestations, including cirrhosis and emphysema, caused by the accumulation of stable polymers of mutant protein in the endoplasmic reticulum of hepatocytes. However, the molecular basis of misfolding and polymerization remain unknown. We produced and crystallized a trimeric form of alpha1AT that is recognized by an antibody specific for the pathological polymer. Unexpectedly, this structure reveals a polymeric linkage mediated by domain swapping the carboxy-terminal 34 residues. Disulphide-trapping and antibody-binding studies further demonstrate that runaway C-terminal domain swapping, rather than the s4A/s5A domain swap previously proposed, underlies polymerization of the common Z-mutant of alpha1AT in vivo.
Molecular basis of alpha1-antitrypsin deficiency revealed by the structure of a domain-swapped trimer.,Yamasaki M, Sendall TJ, Pearce MC, Whisstock JC, Huntington JA EMBO Rep. 2011 Sep 30;12(10):1011-7. doi: 10.1038/embor.2011.171. PMID:21909074[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
- ↑ Yamasaki M, Sendall TJ, Pearce MC, Whisstock JC, Huntington JA. Molecular basis of alpha1-antitrypsin deficiency revealed by the structure of a domain-swapped trimer. EMBO Rep. 2011 Sep 30;12(10):1011-7. doi: 10.1038/embor.2011.171. PMID:21909074 doi:http://dx.doi.org/10.1038/embor.2011.171
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