Long distance interactions within the potassium channel pore are revealed by molecular diversity of viral proteins.
Kcv is a 94-amino acid protein encoded by chlorella virus PBCV-1 that corresponds to the pore module of K(+) channels. Therefore, Kcv can be a model for studying the protein design of K(+) channel pores. We analyzed the molecular diversity generated by approximately 1 billion years of evolution on kcv genes isolated from 40 additional chlorella viruses. Because the channel is apparently required for virus replication, the Kcv variants are all functional and contain multiple and dispersed substitutions that represent a repertoire of allowed sets of amino acid substitutions (from 4 to 12 amino acids). Correlations between amino acid substitutions and the new properties displayed by these channels guided site-directed mutations that revealed synergistic amino acid interactions within the protein as well as previously unknown interactions between distant channel domains. The effects of these multiple changes were not predictable from a priori structural knowledge of the channel pore.
Gazzarrini
Sabrina
S
Department of Biology and Consiglio Nazionale delle Ricerche Istituto di Biofisica-Mi, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
Kang
Ming
M
Van Etten
James L
JL
Tayefeh
Sascha
S
Kast
Stefan M
SM
DiFrancesco
Dario
D
Thiel
Gerhard
G
Moroni
Anna
A
D000595:Amino Acid Sequence; D002586:Cesium / Q000737:chemistry; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000378:metabolism; D004594:Electrophysiology; D007477:Ions; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000737:chemistry
D018076:DNA, Complementary; D007477:Ions; D015221:Potassium Channels; D014764:Viral Proteins; D002586:Cesium