Lanreotide

Helical Index practice #2

Power spectrum dimension: 1024 x 1024 pixel,
0.85 Å/px. Method (spider, old method)

Lanreotide tube rmax and rmin: 151Å and 80Å

Download Power spectrum

Checkpoint

which two layer-lines (LL) were used? 

Note, there may be multiple acceptable answers to this question.  Format: LL (R, Z)
LL (15, 44.5)
LL (15, 16.5)

Hint: LL (???, 122) = 2* LL (15, 44.5) + 2* LL (15, 16.5).
LL(122) is close to meridian, meaning it has to be a very small Bessel order. So, LL(44.5) and LL(16.5) must have different hand. In other word, one is "+" and the other is "-"

What are the possible Bessel order ranges for those two vectors?

LL (15, 44.5) :
       2*π*R*rmax = 2 * 3.14 * (15/1024/0.85) * 151 = 16                          Bessel order n ≤ 14
       2*π*R*rmin = 2 * 3.14 * (15/1024/0.85) * 80 = 8.6                         Bessel order n ≥ 10

LL (15, 16.5):
       same range, 10-14

What are the possible symmetries?

What's the correct symmetry (quickly check whether it is in your list)

point group: C1
helical rise: 1.04Å
helical twist: 26.2 degrees

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