title: Structural and functional insights into an archaeal L-asparaginase obtained through the linker-less assembly of constituent domains.
abstract: Covalent linkers bridging the domains of multidomain proteins are considered to be crucial for assembly and function. In this report, an exception in which the linker of a two-domain dimeric L-asparaginase from Pyrococcus furiosus (PfA) was found to be dispensable is presented. Domains of this enzyme assembled without the linker into a conjoined tetrameric form that exhibited higher activity than the parent enzyme. The global shape and quaternary structure of the conjoined PfA were also similar to the wild-type PfA, as observed by their solution scattering profiles and X-ray crystallographic data. Comparison of the crystal structures of substrate-bound and unbound enzymes revealed an altogether new active-site composition and mechanism of action. Thus, conjoined PfA is presented as a unique enzyme obtained through noncovalent, linker-less assembly of constituent domains that is stable enough to function efficiently at elevated temperatures.
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India.
authors.forename: Rachana
authors.initials: R
authors.lastname: Tomar
authors.affiliation: CSIR - Institute of Microbial Technology, Chandigarh, India.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Sharma
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India.
authors.forename: Ankit
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Bansal
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India.
authors.forename: Bishwajit
authors.initials: B
authors.lastname: Kundu
mesh_terms: D000595:Amino Acid Sequence; D001215:Asparaginase / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D020027:Pyrococcus furiosus / Q000737:chemistry / Q000201:enzymology*; D053838:Scattering, Small Angle; D016415:Sequence Alignment; D014961:X-Ray Diffraction
chemical_list: D001215:Asparaginase
keywords: Pyrococcus furiosus; l-asparaginase; linker-less assembly