title: Effect of artemin on structural transition of β-lactoglobulin.
abstract: Encysted embryos of Artemia are exceptionally resistant to severe environmental stress. This resistance is thought to depend in part on the existence of a protein termed artemin. There is only little information about the function of artemin. It has been reported artemin is a thermostable protein with RNA-binding ability. In addition, it reduces the extent of aggregation significantly and enhances the efficiency of refolding and activity recovery of carbonic anhydrase and horseradish peroxidase. In this study, the effect of artemin purified from Artemia urmiana on bovine β-lactoglobulin (BLG) and its α-helical intermediate state has been evaluated by circular dichroism and intrinsic and extrinsic fluorescence spectroscopy. The results obtained in aqueous buffer show, artemin decreases the compactness of BLG structure and causes to the exposure of some hydrophobic groups. The results also indicate artemin has an inhibitory effect on β-sheet→α-helix transition in the secondary structure of β-lactoglobulin. Since this transition occurs during unfolding of β-lactoglobulin, it seems artemin influences on the folding pathway of β-lactoglobulin. This structural effect of artemin can result from its high surface hydrophobicity. Consequently, it is expected that artemin has chaperoning potency because of its effect on the folding of BLG.
authors.affiliation: Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45195-1159, Iran. hasani@iasbs.ac.ir
authors.forename: Leila
authors.initials: L
authors.lastname: Hassani
authors.forename: Reza H
authors.initials: RH
authors.lastname: Sajedi
mesh_terms: D000818:Animals; D001156:Artemia / Q000737:chemistry* / Q000196:embryology / Q000378:metabolism; D060829:Arthropod Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D002942:Circular Dichroism; D057927:Hydrophobic and Hydrophilic Interactions; D033862:Iron-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007782:Lactoglobulins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D017510:Protein Folding; D025941:Protein Interaction Mapping; D017433:Protein Structure, Secondary; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D060829:Arthropod Proteins; D033862:Iron-Binding Proteins; D007782:Lactoglobulins; D016601:RNA-Binding Proteins; C490888:artemin protein, brine shrimp