Question

1. Consider a circular, duplex DNA of 6300 bp entirely in B-form (10.5 bp/turn). a. What are the values of Tw and Lk? ? b. If this circular DNA is isolated from a cell, and has a superhelical density, ? = - 0.06, (where ? = ?Lk/Lk?) while remaining in B-form, what are Lk, Tw, and Wr? c. After isolation of the superhelical DNA from part b, Z-DNA binding proteins are added, and 504 bp of B-form DNA (10.5 bp per turn) are converted to Z-form (12 bp/turn). Calculate the new values of Lk, Tw, and Wr. d. Is the DNA in step c) negatively-supercoiled, positively-supercoiled, or relaxed?

          1. Consider a circular, duplex DNA of 6300 bp entirely in B-form (10.5 bp/turn).
a. What are the values of Tw and Lk? ?
b. If this circular DNA is isolated from a cell, and has a superhelical density, ? = - 0.06, (where ? = ?Lk/Lk?) while remaining in B-form, what are Lk, Tw, and Wr?
c. After isolation of the superhelical DNA from part b, Z-DNA binding proteins are added, and 504 bp of B-form DNA (10.5 bp per turn) are converted to Z-form (12 bp/turn). Calculate the new values of Lk, Tw, and Wr.
d. Is the DNA in step c) negatively-supercoiled, positively-supercoiled, or relaxed?

1. Consider a circular, duplex DNA of 6300 bp entirely in B-form (10.5 bp/turn).
a. What are the values of Tw and Lk? ?
b. If this circular DNA is isolated from a cell, and has a superhelical density, ? = - 0.06, (where ? = ?Lk/Lk?) while remaining in B-form, what are Lk, Tw, and Wr?
c. After isolation of the superhelical DNA from part b, Z-DNA binding proteins are added, and 504 bp of B-form DNA (10.5 bp per turn) are converted to Z-form (12 bp/turn). Calculate the new values of Lk, Tw, and Wr.
d. Is the DNA in step c) negatively-supercoiled, positively-supercoiled, or relaxed?

Added by Henry B.

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