Bioinformatic and mutational analysis of channelrhodopsin-2 protein cation-conducting pathway

Anna Pia Plazzo, Nicola De Franceschi, Francesca Da Broi, Francesco Zonta, Maria Federica Sanasi, Francesco Filippini, Marco Mongillo*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Channelrhodopsin-2 (ChR2) is a light-gated cation channel widely used as a biotechnological tool to control membrane depolarization in various cell types and tissues. Although several ChR2 variants with modified properties have been generated, the structural determinants of the protein function are largely unresolved. We used bioinformatic modeling of the ChR2 structure to identify the putative cationic pathway within the channel, which is formed by a system of inner cavities that are uniquely present in this microbial rhodopsin. Site-directed mutagenesis combined with patch clamp analysis in HeLa cells was used to determine key residues involved in ChR2 conductance and selectivity. Among them, Gln-56 is important for ion conductance, whereas Ser-63, Thr-250, and Asn-258 are previously unrecognized residues involved in ion selectivity and photocurrent kinetics. This study widens the current structural information on ChR2 and can assist in the design of new improved variants for specific biological applications.

Original languageEnglish
Pages (from-to)4818-4825
Number of pages8
JournalJournal of Biological Chemistry
Issue number7
Publication statusPublished - 10 Feb 2012
Externally publishedYes


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