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Figure 2.
Fig. 2. (A) Overview of the hPrp31^78-333–15.5K–U4 5'-SL
complex (left). hPrp31^78-333, blue; 15.5K, red; RNA, gold. RNA
elements not seen in the binary 15.5K–22-mer RNA complex with
a shorter stem I [right (12); PDB ID 1E7K] are in green.
Positions A194 and A216, at which missense mutations have been
linked to the RP11 form of retinitis pigmentosa, are shown as
space-filling models and colored cyan. Dashed line in
hPrp31^78-333, disordered loop. Dashed line in the binary
complex, unstructured pentaloop. Although induced-fit
interactions are the hallmark of most RNA-protein complexes
(32), the structuring of the RNA pentaloop upon hPrp31^78-333
binding observed here is particularly pronounced. The crystal
structure contains two crystallographically independent ternary
complexes per asymmetric unit that are largely identical (table
S2). (B) Close-up views of the complex from the back (left) and
from the bottom (right). Main contact regions between
hPrp31^78-333 and 15.5K and between hPrp31^78-333 and the RNA
are indicated by connecting lines and are labeled by letters and
numbers, respectively. Regions of the RNA are color-coded:
distal portion of stem I, gray; K-turn region, gold; distal
portion of stem II, brown; and pentaloop, beige. The bulged-out
U31 denotes the tip of the K turn and is shown in sticks.
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