Introduction: The giant muscular proteins titin and obscurin bind to each other at the Zdisk
during muscle development. This binding event is mediated through two domains from each
protein: ZIg9/10 from titin and Ig58/59 from obscurin. This interaction helps stabilize and organize
the sarcomere; ablation of this binding leads to muscular dystrophy.
Objective: Here we solve the high-resolution solution structure of titin ZIg10 and further delineate
which sections of titin bind to obscurin.
Materials and Methods: Solution NMR, Circular Dichroism, and SEC-MALS were used to biophysically
characterize the titin domains involved in this titin-obscurin interaction.
Results and Conclusion: We present the high-resolution solution structure of titin ZIg10. Additionally,
we show that titin ZIg9 drives the titin-obscurin interaction, while ZIg10 does not actively
participate in the titin-obscurin interaction but instead acts to stabilize ZIg9.