Biology Reference
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B
A
C
10Å
4.7Å
Lamination
10Å
10Å
D
4.7Å
Figure 1.2
Cartoon of cross-
β
fiber composed of anti-parallel
β
-sheets,
in both (
) space filling with all atoms shown, depicting
the tightly packed side-chain atoms within the fiber, and
(
A
) stick format displaying only the peptide back bone.
The anti-parallel
B, C
-sheet organization depends on the K-E
cross-strand pairing as shown in (
β
).The distance between
H-bonded peptides within a single
D
β
-sheet is 4.7 Å. (
C
)
β
-Sheets stack perpendicular to the H-bonding direction with
a distance between adjacent
-sheets of ~10 Å, determined
by side-chain length. For the model in the illustration, two
peptides with
β
β
-strand lengths of ~24 Å align end-to-end
β
×
and 5
-sheets are laminated to form a fiber with a 50 Å
50
×
Å (i.e., 5 nm
5 nm) cross section. In the space-filling model
(
A
) and (
D
), K is colored blue and E is red. In (
B
) and (
C
),
peptides within individual
β
-sheets have the same color.
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