5TR1

Cryo-electron microscopy structure of a bovine CLC-K chloride channel, alternate (class 2) conformation

Summary for 5TR1

• Entry DOI: 10.2210/pdb5tr1/pdb
• Related: 5TQQ
• EMDB information: 8435 8454
• Descriptor: Chloride channel protein, Monoclonal antibody, Fab fragment, heavy chain, Monoclonal antibody, Fab fragment, light chain, ... (4 entities in total)
• Functional Keywords: clc, chloride channel, membrane, kidney, transport protein
• Biological source: Bos taurus (Bovine); More
• Total number of polymer chains: 6
• Total formula weight: 196930.76

Authors

Park, E.,MacKinnon, R. (deposition date: 2016-10-25, release date: 2017-01-11, Last modification date: 2024-10-23)

Primary citation

Park, E.,Campbell, E.B.,MacKinnon, R.
Structure of a CLC chloride ion channel by cryo-electron microscopy.
Nature, 541:500-505, 2017

PubMed Abstract: CLC proteins transport chloride (Cl) ions across cellular membranes to regulate muscle excitability, electrolyte movement across epithelia, and acidification of intracellular organelles. Some CLC proteins are channels that conduct Cl ions passively, whereas others are secondary active transporters that exchange two Cl ions for one H. The structural basis underlying these distinctive transport mechanisms is puzzling because CLC channels and transporters are expected to share the same architecture on the basis of sequence homology. Here we determined the structure of a bovine CLC channel (CLC-K) using cryo-electron microscopy. A conserved loop in the Cl transport pathway shows a structure markedly different from that of CLC transporters. Consequently, the cytosolic constriction for Cl passage is widened in CLC-K such that the kinetic barrier previously postulated for Cl/H transporter function would be reduced. Thus, reduction of a kinetic barrier in CLC channels enables fast flow of Cl down its electrochemical gradient.

PubMed: 28002411
DOI: 10.1038/nature20812

Experimental method

ELECTRON MICROSCOPY (3.95 Å)