title: Alpha 1-antitrypsin polymerization: a fluorescence correlation spectroscopic study.
abstract: Alpha(1)-antitrypsin (AT) is the most abundantly circulating human proteinase inhibitor in the serpin family. The polymerization of AT, leading to alpha(1)-antitrypsin deficiency, has been studied extensively in vitro by a variety of ensemble methods. Here we report the use of fluorescence correlation spectroscopy to gain further insight into this process. Measurements of the distributions of diffusion times of polymerizing AT, carried out at 45, 50, and 55 degrees C, clearly show the existence of a kinetic lag phase, during which short oligomers are formed, prior to the formation of heterogeneous mixtures of longer polymers, and suggest that long polymers, which appear to be metastable, are produced through the condensation of shorter oligomers.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Pradipta
authors.initials: P
authors.lastname: Purkayastha
authors.forename: Jason W
authors.initials: JW
authors.lastname: Klemke
authors.forename: Stacey
authors.initials: S
authors.lastname: Lavender
authors.forename: Rolando
authors.initials: R
authors.lastname: Oyola
authors.forename: Barry S
authors.initials: BS
authors.lastname: Cooperman
authors.forename: Feng
authors.initials: F
authors.lastname: Gai
mesh_terms: D003545:Cysteine / Q000235:genetics; D004058:Diffusion; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism*; D011489:Protein Denaturation / Q000235:genetics; D012694:Serine / Q000235:genetics; D013050:Spectrometry, Fluorescence / Q000379:methods; D013696:Temperature; D013997:Time Factors; D000515:alpha 1-Antitrypsin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D011108:Polymers; D000515:alpha 1-Antitrypsin; D012694:Serine; D003545:Cysteine