title: New aminopeptidase from "microbial dark matter" archaeon.
abstract: Marine sediments host a large population of diverse, heterotrophic, uncultured microorganisms with unknown physiologies that control carbon flow through organic matter decomposition. Recently, single-cell genomics uncovered new key players in these processes, such as the miscellaneous crenarchaeotal group. These widespread archaea encode putative intra- and extracellular proteases for the degradation of detrital proteins present in sediments. Here, we show that one of these enzymes is a self-compartmentalizing tetrameric aminopeptidase with a preference for cysteine and hydrophobic residues at the N terminus of the hydrolyzed peptide. The ability to perform detailed characterizations of enzymes from native subsurface microorganisms, without requiring that those organisms first be grown in pure culture, holds great promise for understanding key carbon transformations in the environment as well as identifying new enzymes for biomedical and biotechnological applications.
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Karolina
authors.initials: K
authors.lastname: Michalska
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Steen
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Gekleng
authors.initials: G
authors.lastname: Chhor
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Endres
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Austen T
authors.initials: AT
authors.lastname: Webber
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Jordan
authors.initials: J
authors.lastname: Bird
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Karen G
authors.initials: KG
authors.lastname: Lloyd
authors.affiliation: *Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois, USA; Department of Microbiology and Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA; and Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA andrzejj@anl.gov.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
mesh_terms: D000626:Aminopeptidases / Q000737:chemistry* / Q000235:genetics; D059001:Aquatic Organisms / Q000201:enzymology* / Q000235:genetics; D001105:Archaea / Q000201:enzymology* / Q000235:genetics; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D000626:Aminopeptidases
keywords: carbon cycle; detrital proteins; marine sediments; single-cell genomics