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PDBsum entry 4xgt
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References listed in PDB file
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Key reference
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Title
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Structure of the frequency-Interacting RNA helicase: a protein interaction hub for the circadian clock.
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Authors
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K.S.Conrad,
J.M.Hurley,
J.Widom,
C.S.Ringelberg,
J.J.Loros,
J.C.Dunlap,
B.R.Crane.
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Ref.
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Embo J, 2016,
35,
1707-1719.
[DOI no: ]
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PubMed id
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Abstract
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In the Neurospora crassa circadian clock, a protein complex of frequency (FRQ),
casein kinase 1a (CK1a), and the FRQ-interacting RNA Helicase (FRH) rhythmically
represses gene expression by the white-collar complex (WCC). FRH crystal
structures in several conformations and bound to ADP/RNA reveal differences
between FRH and the yeast homolog Mtr4 that clarify the distinct role of FRH in
the clock. The FRQ-interacting region at the FRH N-terminus has variable
structure in the absence of FRQ A known mutation that disrupts circadian rhythms
(R806H) resides in a positively charged surface of the KOW domain, far removed
from the helicase core. We show that changes to other similarly located residues
modulate interactions with the WCC and FRQ A V142G substitution near the
N-terminus also alters FRQ and WCC binding to FRH, but produces an unusual short
clock period. These data support the assertion that FRH helicase activity does
not play an essential role in the clock, but rather FRH acts to mediate contacts
among FRQ, CK1a and the WCC through interactions involving its N-terminus and
KOW module.
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