AI Article Synopsis
- The study investigates the previously under-characterized N- and C-termini of the KcsA potassium channel, using advanced techniques like HR-MAS NMR and fractional deuteration.
- The findings reveal that the C-terminus shifts from a rigid to a more dynamic structure as the environment becomes acidic, which is crucial for understanding its function.
- Additionally, the research highlights how a C-terminal mutation destabilizes the channel's selectivity filter and notes lipid hydrolysis effects within the experimental setups.
Article Abstract
The structure of the transmembrane domain of the pH-activated bacterial potassium channel KcsA has been extensively characterized, yet little information is available on the structure of its cytosolic, functionally critical N- and C-termini. This study presents high-resolution magic angle spinning (HR-MAS) and fractional deuteration as tools to study these poorly resolved regions for proteoliposome-embedded KcsA. Using H-detected HR-MAS NMR, we show that the C-terminus transitions from a rigid structure to a more dynamic structure as the solution is rendered acidic. We make previously unreported assignments of residues in the C-terminus of lipid-embedded channels. These data agree with functional models of the C-terminus-stabilizing KcsA tetramers at a neutral pH with decreased stabilization effects at acidic pH. We present evidence that a C-terminal truncation mutation has a destabilizing effect on the KcsA selectivity filter. Finally, we show evidence of hydrolysis of lipids in proteoliposome samples during typical experimental timeframes.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9405666 | PMC |
| http://dx.doi.org/10.3390/biom12081122 | DOI Listing |
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