title: Structural and functional characterization of a novel type-III dockerin from Ruminococcus flavefaciens.
abstract: Phylogenetic analysis of known dockerins in Ruminococcus flavefaciens revealed a novel subtype, type-III, in the scaffoldin proteins, ScaA, ScaB, ScaC and ScaE. In this study, we explored the Ca²⁺-binding properties of the type-III dockerin from the ScaA scaffoldin (ScaADoc) using a battery of structural and biophysical approaches including circular dichroism spectroscopy, isothermal titration calorimetry, differential scanning calorimetry, and nuclear magnetic resonance spectroscopy. Despite the lack of a second canonical Ca²⁺-binding loop, the behaviour of ScaADoc is similar with respect to other dockerin protein modules in terms of its responsiveness to Ca²⁺ and affinity for the cohesin from the ScaB scaffoldin. Our results highlight the robustness of dockerin modules and how their Ca²⁺-binding properties can be exploited in the construction of designer cellulosomes.
authors.affiliation: Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Alon
authors.initials: A
authors.lastname: Karpol
authors.forename: Maroor K
authors.initials: MK
authors.lastname: Jobby
authors.forename: Michal
authors.initials: M
authors.lastname: Slutzki
authors.forename: Ilit
authors.initials: I
authors.lastname: Noach
authors.forename: Seth
authors.initials: S
authors.lastname: Chitayat
authors.forename: Steven P
authors.initials: SP
authors.lastname: Smith
authors.forename: Edward A
authors.initials: EA
authors.lastname: Bayer
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002152:Calorimetry, Differential Scanning; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D044603:Cellulosomes / Q000737:chemistry / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002942:Circular Dichroism; D020832:EF Hand Motifs; D057927:Hydrophobic and Hydrophilic Interactions; D046912:Multiprotein Complexes / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010802:Phylogeny; D017510:Protein Folding; D054730:Protein Interaction Domains and Motifs; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D045857:Ruminococcus / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013499:Surface Properties; D000097722:Cohesins
chemical_list: D001426:Bacterial Proteins; D002118:Calcium; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D000097722:Cohesins; C422913:ScaA protein, Ruminococcus; C422914:ScaB protein, Ruminococcus