Structure-function analysis of the ion channel selectivity filter in human annexin V.
Electrophysiology and structural studies were performed on an annexin V variant containing a mutation of glutamic acid-95 to serine in the center of the pore region. The mutation resulted in a lower single channel conductance for calcium and a strongly increased conductance for sodium and potassium, indicating that glutamic acid-95 is a crucial constituent of the ion selectivity filter. There were only minor differences in the crystal structures of mutant and wild-type annexin V around the mutation site; however, the mutant showed structural differences elsewhere, including the presence of a calcium binding site in domain III unrelated to the mutation. Analysis of the membrane-bound form of annexin V by electron microscopy revealed no differences between the wild type and mutant.
Berendes
R
R
Max-Planck-Institut für Biochemie, Martinsried, Germany.
Voges
D
D
Demange
P
P
Huber
R
R
Burger
A
A
D017304:Annexin A5 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D003196:Computer Graphics; D018360:Crystallography, X-Ray; D004553:Electric Conductivity; D005971:Glutamates / Q000737:chemistry; D018698:Glutamic Acid; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D008854:Microscopy, Electron; D016297:Mutagenesis, Site-Directed; D011188:Potassium / Q000378:metabolism; D017433:Protein Structure, Secondary; D012694:Serine / Q000737:chemistry; D012964:Sodium / Q000378:metabolism; D013329:Structure-Activity Relationship
D017304:Annexin A5; D005971:Glutamates; D007473:Ion Channels; D018698:Glutamic Acid; D012694:Serine; D012964:Sodium; D011188:Potassium; D002118:Calcium