title: Assembly of Ruminococcus flavefaciens cellulosome revealed by structures of two cohesin-dockerin complexes.
abstract: Cellulosomes are sophisticated multi-enzymatic nanomachines produced by anaerobes to effectively deconstruct plant structural carbohydrates. Cellulosome assembly involves the binding of enzyme-borne dockerins (Doc) to repeated cohesin (Coh) modules located in a non-catalytic scaffoldin. Docs appended to cellulosomal enzymes generally present two similar Coh-binding interfaces supporting a dual-binding mode, which may confer increased positional adjustment of the different complex components. Ruminococcus flavefaciens' cellulosome is assembled from a repertoire of 223 Doc-containing proteins classified into 6 groups. Recent studies revealed that Docs of groups 3 and 6 are recruited to the cellulosome via a single-binding mode mechanism with an adaptor scaffoldin. To investigate the extent to which the single-binding mode contributes to the assembly of R. flavefaciens cellulosome, the structures of two group 1 Docs bound to Cohs of primary (ScaA) and adaptor (ScaB) scaffoldins were solved. The data revealed that group 1 Docs display a conserved mechanism of Coh recognition involving a single-binding mode. Therefore, in contrast to all cellulosomes described to date, the assembly of R. flavefaciens cellulosome involves single but not dual-binding mode Docs. Thus, this work reveals a novel mechanism of cellulosome assembly and challenges the ubiquitous implication of the dual-binding mode in the acquisition of cellulosome flexibility.
authors.affiliation: CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Bule
authors.affiliation: CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal.
authors.forename: Victor D
authors.initials: VD
authors.lastname: Alves
authors.affiliation: Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Vered
authors.initials: V
authors.lastname: Israeli-Ruimy
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
authors.forename: Ana L
authors.identifier: http://orcid.org/0000-0002-3824-0240
authors.initials: AL
authors.lastname: Carvalho
authors.affiliation: CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal.
authors.forename: Luís M A
authors.initials: LMA
authors.lastname: Ferreira
authors.affiliation: Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Smith
authors.affiliation: Institute for Cell and Molecular Biosciences, Newcastle University, The Medical School, Newcastle upon Tyne, NE2 4HH, United Kingdom.
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Gilbert
authors.affiliation: CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal.
authors.forename: Shabir
authors.initials: S
authors.lastname: Najmudin
authors.affiliation: Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Bayer
authors.affiliation: CIISA - Faculdade de Medicina Veterinária, ULisboa, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal. cafontes@fmv.ulisboa.pt.
authors.forename: Carlos M G A
authors.initials: CMGA
authors.lastname: Fontes
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism*; D044603:Cellulosomes / Q000737:chemistry* / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000378:metabolism*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D045857:Ruminococcus / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D000097722:Cohesins
chemical_list: D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D046912:Multiprotein Complexes; D000097722:Cohesins