Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Repeating intermolecular protein association by means of beta-sheet expansion is the mechanism underlying a multitude of diseases including Alzheimer's, Huntington's and Parkinson's and the prion encephalopathies. A family of proteins, known as the serpins, also forms large stable multimers by ordered beta-sheet linkages leading to intracellular accretion and disease. These 'serpinopathies' include early-onset dementia caused by mutations in neuroserpin, liver cirrhosis and emphysema caused by mutations in alpha(1)-antitrypsin (alpha(1)AT), and thrombosis caused by mutations in antithrombin. Serpin structure and function are quite well understood, and the family has therefore become a model system for understanding the beta-sheet expansion disorders collectively known as the conformational diseases. To develop strategies to prevent and reverse these disorders, it is necessary to determine the structural basis of the intermolecular linkage and of the pathogenic monomeric state. Here we report the crystallographic structure of a stable serpin dimer which reveals a domain swap of more than 50 residues, including two long antiparallel beta-strands inserting in the centre of the principal beta-sheet of the neighbouring monomer. This structure explains the extreme stability of serpin polymers, the molecular basis of their rapid propagation, and provides critical new insights into the structural changes which initiate irreversible beta-sheet expansion.
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PMID:Crystal structure of a stable dimer reveals the molecular basis of serpin polymerization. 1897 12

Point mutations cause members of the serine protease inhibitor (serpin) superfamily to undergo a novel conformational transition, forming ordered polymers. These polymers characterize a group of diseases termed the serpinopathies. The formation of polymers underlies the retention of alpha(1)-antitrypsin within hepatocytes and of neuroserpin within neurons to cause cirrhosis and dementia, respectively. Point mutations of antithrombin, C1 inhibitor, alpha(1)-antichymotrypsin, and heparin cofactor II cause a similar conformational transition, resulting in a plasma deficiency that is associated with thrombosis, angioedema, and emphysema. Polymers of serpins can also form in extracellular tissues where they activate inflammatory cascades. This is best described for the Z variant of alpha(1)-antitrypsin in which the proinflammatory properties of polymers provide an explanation for both progressive emphysema and the selective advantage of this mutant allele. Therapeutic strategies are now being developed to block the aberrant conformational transitions and so treat the serpinopathies.
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PMID:Conformational pathology of the serpins: themes, variations, and therapeutic strategies. 1924 36

Serine Protease inhibitors (serpins) are a super-family of proteins that controls the proteinases involved in the inflammation, complementation, coagulation and fibrinolytic pathways. Serpins are prone to conformational diseases due to a complex inhibition mechanism that involves large scale conformational change, and their susceptibility to undergo point mutations might lead to functional defects. Serpins are associated with diseases like emphysema/cirrhosis, angioedema, familial dementia, chronic obstructive bronchitis and thrombosis. Serpin polymerization based pathologies are fairly widespread and devising a cure has been difficult due to lack of clarity regarding its mechanism. Serpin can exist in various conformational states and has a variable cofactor binding ability. It has a large genome and proteome database which can be utilized to gain critical insight into their structure, mechanism and defects. Comprehensive computational studies on the serpin family is lacking, most of the work done till date is limited and deals mostly with few individual serpins. We have tried to analyze few aspect of this family using diverse computational biology tools and have shown the following: a) the importance of residue burial linked shift in the conformational stability as a major factor in increasing the polymer propensity in serpins. b) Amino acids involved in the polymerization are in general completely buried in the native conformation. c) An isozyme specific antithrombin study showed the structural basis of improved heparin binding to beta antithrombin as compared to alpha-antithrombin. d) A comprehensive cavity analysis showed its importance in inhibition and polymerizaiton and finally e) an interface analysis of various serpin protease complexes identified critical evolutionary conserved residues in exosite that determines its protease specificity. This work introduces the problem and emphasizes on the need for in-depth computational studies of serpin superfamily.
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PMID:Structure function analysis of serpin super-family: "a computational approach". 2385 65


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