  Twisted bilayer graphene (tBLG) has emerged as an exciting platform for novel
condensed matter physics. However, electron-phonon ($e$-ph) interactions in
tBLG and their effects on electronic transport are not completely understood.
Here we show first-principles calculations of $e$-ph interactions and
resistivity in commensurate tBLG with large twist angles of 13.2 and 21.8
degrees. These calculations overcome key technical barriers, including large
unit cells of up to 76 atoms, Brillouin-zone folding of the $e$-ph
interactions, and unstable lattice vibrations due to the AA-stacked domains. We
show that $e$-ph interactions due to layer-breathing (LB) phonons enhance
intervalley scattering in large-angle tBLG. This interaction effectively
couples the two layers, which are otherwise electronically decoupled at such
large twist angles. As a result, the phonon-limited resistivity in tBLG
deviates from the temperature-linear trend characteristic of monolayer graphene
and tBLG near the magic angle. Taken together, our work quantifies $e$-ph
interactions and scattering mechanisms in tBLG, revealing subtle interlayer
coupling effects at large twist angles.
