# Probing functional mechanisms in K+ channels using unnatural mutagenesis

> **NIH NIH R01** · OREGON HEALTH & SCIENCE UNIVERSITY · 2020 · $331,014

## Abstract

Voltage gated K+ (Kv) channels couple the flux of K+ to the membrane potential and play key
roles in the brain and heart. Mutations in Kv channels can cause severe diseases in humans
such as epilepsies and cardiac arrhythmias. There have been major advances in the structure
determination of Kv channels. In spite of the structural information available, there are major
questions on the functional mechanisms in Kv channels that remain unanswered. Here we
investigate the processes of voltage gating and C-type inactivation that regulate the flux of K+
through Kv channels. We use a multidisciplinary approach centered on unnatural amino acid
(UAA) mutagenesis in our investigations. UAA mutagenesis is a very powerful method for
protein modification, compared to traditional mutagenesis, because it allows a large variety of
side chain modifications and also permits the modification of the protein backbone. We use this
approach to investigate the role of the main chain H-bonds in the fourth transmembrane helix
(TM4) in voltage gating of the Shaker K+ channel and the hyperpolarization activated and cyclic
nucleotide gated ion channel HCN (aim 1). We investigate the role of ion binding sites in the
selectivity filter of the Shaker channel in C-type inactivation and we complement the functional
studies on Shaker with structural studies on the KvAP channel, an archaeal homolog of the
Shaker channel (aim 2). We also investigate the mechanism of C-type inactivation in the hERG
K+ channel, which has interesting functional differences from C-type inactivation in the Shaker
channel and is physiologically critical for normal cardiac function (Aim 3). The research
proposed is significant as it provides greater insight into the functional mechanisms of voltage
gating and C-type inactivation in Kv channels. The research is also significant as it will provide a
general strategy for using UAA mutagenesis to investigate the role of main chain H-bonds and
ion binding sites, which are important for function in many families of membrane proteins.

## Key facts

- **NIH application ID:** 10000155
- **Project number:** 5R01GM087546-11
- **Recipient organization:** OREGON HEALTH & SCIENCE UNIVERSITY
- **Principal Investigator:** Francis Valiyaveetil
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $331,014
- **Award type:** 5
- **Project period:** 2009-05-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10000155

## Citation

> US National Institutes of Health, RePORTER application 10000155, Probing functional mechanisms in K+ channels using unnatural mutagenesis (5R01GM087546-11). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10000155. Licensed CC0.

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