Natural Design of a Stabilized Cross‐β Fold: Structure of the FuA <i>FapC</i> from <i>Pseudomonas</i> Sp. UK4 Reveals a Critical Role for Stacking of Imperfect Repeats
Abstract
Abstract An essential structural component of bacterial biofilms is functional amyloid (FuA), which also has great potential as an engineerable nano‐biomaterial. However, experimentally based high resolution structures of FuA that resolve individual residues are lacking. A fully experimentally based 3.2 Å resolution cryo‐electron microscopy density map of the FuA protein FapC from Pseudomonas sp. UK4 is presented, which reveals a Greek key‐shaped protofilament. The structure supports bioinformatic identification of conserved motifs and is broadly consistent with the AlphaFold prediction but with important modifications. Each FapC monomer consists of three imperfect repeats (IRs), with each repeat forming one cross‐β layer. An array of highly conserved Asn and Gln residues with an extensive H‐bonding network underpins this conserved Greek key‐shape and reveals the role of heterogeneous cross‐β stacking in amyloid cross‐seeding. The covariation of residues in the hydrophobic core among different IRs suggests a cooperative monomer folding process during fibril elongation, while heterogeneous stacking of IRs reduces charge repulsion between layers to stabilize the monomer fold. The FapC fibrils show intrinsic catalytic activity and strain‐dependent nanomechanical properties. Combined with mutagenesis data, the structure provides mechanistic insights into formation of FapC FuA from disordered monomers and a structural foundation for the design of novel biomaterials.
Article Details
Authors (14)
Yanting Jiang
Department of Clinical Laboratory the First Affiliated Hospital of Guangxi Medical University Key Laboratory of Clinical Laboratory Medicine of Guangxi Department of Education Guangxi Key Laboratory of Enhanced Recovery after Surgery for Gastrointestinal Cancer Shuangyong Road 6, Guangxi Zhuang Autonomous Region Nanning 530021 China
Samuel Peña‐Díaz
EnZync Center for Enzymatic Deconstruction of Thermoset Plastics Aarhus Denmark
Zhefei Zhang
Department of Clinical Laboratory the First Affiliated Hospital of Guangxi Medical University Key Laboratory of Clinical Laboratory Medicine of Guangxi Department of Education Guangxi Key Laboratory of Enhanced Recovery after Surgery for Gastrointestinal Cancer Shuangyong Road 6, Guangxi Zhuang Autonomous Region Nanning 530021 China
Anders Ogechi Hostrup Daugberg
Department of Chemistry and Bioscience Aalborg University Fredrik Bajers Vej 7H Aalborg OE 9220 Denmark
Marcos López Hernández
Interdisciplinary Nanoscience Center (iNANO) Aarhus University Gustav Wieds Vej 14 Aarhus C 8000 Denmark
Janni Nielsen
Qiaojie Huang
Department of Clinical Laboratory the First Affiliated Hospital of Guangxi Medical University Key Laboratory of Clinical Laboratory Medicine of Guangxi Department of Education Guangxi Key Laboratory of Enhanced Recovery after Surgery for Gastrointestinal Cancer Shuangyong Road 6, Guangxi Zhuang Autonomous Region Nanning 530021 China
Shenghan Qin
Department of Clinical Laboratory the First Affiliated Hospital of Guangxi Medical University Key Laboratory of Clinical Laboratory Medicine of Guangxi Department of Education Guangxi Key Laboratory of Enhanced Recovery after Surgery for Gastrointestinal Cancer Shuangyong Road 6, Guangxi Zhuang Autonomous Region Nanning 530021 China
Morten K. D. Dueholm
Department of Chemistry and Bioscience Aalborg University Fredrik Bajers Vej 7H Aalborg OE 9220 Denmark
Mingdong Dong
Interdisciplinary Nanoscience Center (iNANO) Aarhus University Gustav Wieds Vej 14 Aarhus C 8000 Denmark
Jan Skov Pedersen
Qin Cao
School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong
Daniel E. Otzen
Huabing Wang