Insights into functional aspects of centrins from the structure of N-terminally extended mouse centrin 1.
Centrins are members of the family of Ca(2+)-binding EF-hand proteins. In photoreceptor cells, centrin isoform 1 is specifically localized in the non-motile cilium. This connecting cilium links the light-sensitive outer segment with the biosynthetic active inner segment of the photoreceptor cell. All intracellular exchanges between these compartments have to occur through this cilium. Three-dimensional structures of centrins from diverse organisms are known, showing that the EF-hand motifs of the N-terminal domains adopt closed conformations, while the C-terminal EF-hand motifs have open conformations. The crystal structure of an N-terminally extended mouse centrin 1 (MmCen1-L) resembles the overall structure of troponin C in its two Ca(2+) bound form. Within the N-terminal extension in MmCen1-L, residues W24 and R25 bind to the C-terminal domain of centrin 1 in a target-protein-like geometry. Here, we discuss this binding mode in connection with putative interaction sites of the target-protein transducin and the self-assembly of centrins.
Park
Jung Hee
JH
Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Ziegelstr. 5-9, D-10098 Berlin, Germany.
Pulvermüller
Alexander
A
Scheerer
Patrick
P
Rausch
Sebastian
S
Giessl
Andreas
A
Höhne
Wolfgang
W
Wolfrum
Uwe
U
Hofmann
Klaus Peter
KP
Ernst
Oliver Peter
OP
Choe
Hui-Woog
HW
Krauss
Norbert
N
D020816:Amino Acid Motifs; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D002923:Cilia / Q000378:metabolism*; D020832:EF Hand Motifs; D006801:Humans; D051379:Mice; D010786:Photoreceptor Cells / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D017385:Sequence Homology; D013329:Structure-Activity Relationship; D020079:Terminal Repeat Sequences
D002135:Calcium-Binding Proteins; D002118:Calcium