Year: 2022
Type: article
Abstract: Copper (Cu) is one of the most abundant trace metals in all organisms, involved in a plethora of cellular processes. Yet elevated concentrations of the element are harmful, and interestingly prokaryotes are more sensitive for environmental Cu stress than humans. Various transport systems are present to maintain intracellular Cu homeostasis, including the prokaryotic plasmid-encoded multiprotein pco operon, which is generally assigned as a defense mechanism against elevated Cu concentrations. Here we structurally and functionally characterize the outer membrane component of the Pco system, PcoB, recovering a 2.0 Å structure, revealing a classical β-barrel architecture. Unexpectedly, we identify a large opening on the extracellular side, linked to a considerably electronegative funnel that becomes narrower towards the periplasm, defining an ion-conducting pathway as also supported by metal binding quantification via inductively coupled plasma mass spectrometry and molecular dynamics (MD) simulations. However, the structure is partially obstructed towards the periplasmic side, and yet flux is permitted in the presence of a Cu gradient as shown by functional characterization in vitro. Complementary in vivo experiments demonstrate that isolated PcoB confers increased sensitivity towards Cu. Aggregated, our findings indicate that PcoB serves to permit Cu import. Thus, it is possible the Pco system physiologically accumulates Cu in the periplasm as a part of an unorthodox defense mechanism against metal stress. These results point to a previously unrecognized principle of maintaining Cu homeostasis and may as such also assist in the understanding and in efforts towards combatting bacterial infections of Pco-harboring pathogens.
Source: Protein Science
DOI: 10.1002/pro.4364
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,950
Funders: Welch Foundation, Agnes og Poul Friis Fond, Vera og Carl Johan Michaelsens Legat, Carl Tryggers Stiftelse för Vetenskaplig Forskning, Carlsbergfondet, Crafoordska Stiftelsen, Lundbeckfonden, Knut och Alice Wallenbergs Stiftelse, Novo Nordisk, Paul Scherrer Institut, Vetenskapsrådet, Danmarks Frie Forskningsfond, Augustinus Fonden, Faculty of Health and Medical Sciences, University of Western Australia, Novo Nordisk Fonden, Hartmann Fonden, H. Lundbeck A/S, DanScatt, National Institutes of Health, Det Sundhedsvidenskabelige Fakultet, Københavns Universitet, National Institute of General Medical Sciences
Awards: G1106556690, G1148555185, G1238694858, G1664882636, G1734421000, G1877407563, G1893318786, G1920020657, G2042407276, G2343226780, G2430567079, G2459838018, G2552791572, G2596370767, G281314274, G289111168, G292835490, G3078839520, G3106080570, G3244335847, G325084317, G3252773853, G3357086232, G3370605335, G3427319507, G3499583756, G3506049996, G351558154, G3518322322, G3632458369, G3740659729, G3899056921, G3989264438, G4056674546, G4244453004, G4249155028, G4375558373, G4596320261, G462323145, G463823130, G4718313952, G4786099349, G4808936127, G4960985608, G5084933454, G5104823421, G5154000508, G521772511, G5378672312, G54641898, G5479358369, G5526518500, G5564989001, G5820163771, G5983305504, G6113440231, Visualizing real-time regulatory dynamics in active membrane transport, G6296791325, G6367454132, G6372444804, G6448517584, G6981076028, G7200791218, G731250434, G73224913, G734170112, G7374589850, Unzipping human zinc-transport, G7489175061, G7528829461, G7633700660, G8215400737, G8393920771, G8489428990, G860412031, G8818087286, G8853233011, G8881924203, G8911029163, Principles of selectivity and translocation in transition metal transporters, metallochaperones, and associated metalloproteins, G947591926, G969451127, G99281538
OpenAlex ID: W4283208643