Ca2+-independent binding of an EF-hand domain to a novel motif in the alpha-actinin-titin complex.
The interaction between alpha-actinin and titin, two modular muscle proteins, is essential for sarcomere assembly. We have solved the solution structure of a complex between the calcium-insensitive C-terminal EF-hand domain of alpha-actinin-2 and the seventh Z-repeat of titin. The structure of the complex is in a semi-open conformation and closely resembles that of myosin light chains in their complexes with heavy chain IQ motifs. However, no IQ motif is present in the Z-repeat, suggesting that the semi-open conformation is a general structural solution for calcium-independent recognition of EF-hand domains.
Atkinson
R A
RA
Division of Molecular Structure, National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA UK.
Joseph
C
C
Kelly
G
G
Muskett
F W
FW
Frenkiel
T A
TA
Nietlispach
D
D
Pastore
A
A
D000185:Actinin / Q000737:chemistry / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D064211:Connectin; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D002135:Calcium-Binding Proteins; D064211:Connectin; D009124:Muscle Proteins; D000185:Actinin; D011494:Protein Kinases; D002118:Calcium