6BX4

The crystal structure of fluoride channel Fluc Ec2 with Monobody S9

Summary for 6BX4

• Entry DOI: 10.2210/pdb6bx4/pdb
• Descriptor: Fluoride ion transporter CrcB, Monobody, FLUORIDE ION, ... (6 entities in total)
• Functional Keywords: fluc, fluoride channel, monobody, transport protein
• Biological source: Escherichia coli; More
• Total number of polymer chains: 4
• Total formula weight: 48232.78

Authors

Turman, D.L.,Miller, C. (deposition date: 2017-12-16, release date: 2018-02-14, Last modification date: 2023-10-04)

Primary citation

Turman, D.L.,Cheloff, A.Z.,Corrado, A.D.,Nathanson, J.T.,Miller, C.
Molecular Interactions between a Fluoride Ion Channel and Synthetic Protein Blockers.
Biochemistry, 57:1212-1218, 2018

PubMed Abstract: Fluoride ion channels of the Fluc family selectively export F ions to rescue unicellular organisms from acute F toxicity. Crystal structures of bacterial Fluc channels in complex with synthetic monobodies, fibronectin-derived soluble β-sandwich fold proteins, show 2-fold symmetric homodimers with an antiparallel transmembrane topology. Monobodies also block Fluc F current via a pore blocking mechanism. However, little is known about the energetic contributions of individual monobody residues to the affinity of the monobody-channel complex or whether the structural paratope corresponds to functional reality. This study seeks to structurally identify and compare residues interacting with Fluc between two highly similar monobodies and subjects them to mutagenesis and functional measurements of equilibrium affinities via a fluorescence anisotropy binding assay to determine their energetic contributions. The results indicate that the functional and structural paratopes strongly agree and that many Tyr residues at the interface, while playing a key role in affinity, can be substituted with Phe and Trp without large disruptions.

PubMed: 29393634
DOI: 10.1021/acs.biochem.7b01272

Experimental method

X-RAY DIFFRACTION (2.55 Å)