title: Structural adaptation of a thermostable biotin-binding protein in a psychrophilic environment.
abstract: Shwanavidin is an avidin-like protein from the marine proteobactrium Shewanella denitrificans, which exhibits an innate dimeric structure while maintaining high affinity toward biotin. A unique residue (Phe-43) from the L3,4 loop and a distinctive disulfide bridge were shown to account for the high affinity toward biotin. Phe-43 emulates the function and position of the critical intermonomeric Trp that characterizes the tetrameric avidins but is lacking in shwanavidin. The 18 copies of the apo-monomer revealed distinctive snapshots of L3,4 and Phe-43, providing rare insight into loop flexibility, binding site accessibility, and psychrophilic adaptation. Nevertheless, as in all avidins, shwanavidin also displays high thermostability properties. The unique features of shwanavidin may provide a platform for the design of a long sought after monovalent form of avidin, which would be ideal for novel types of biotechnological application.
authors.affiliation: Department of Biological Chemistry, the Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel.
authors.forename: Amit
authors.initials: A
authors.lastname: Meir
authors.forename: Edward A
authors.initials: EA
authors.lastname: Bayer
authors.forename: Oded
authors.initials: O
authors.lastname: Livnah
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013696:Temperature
chemical_list: D002352:Carrier Proteins; C017071:biotin-binding proteins