{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture11_NABPty2012 (1)

J r huth et al nature struct biol 4 657 1997 2ezepdb

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: high temperatures If the temperature is lowered, the strands recombine. The rate of recombination is inversely proportional to the complexity of the DNA. 100 80 % Denatured The temperature at which this “denaturation” or “melting” occurs (tm) depends on the pH and salt concentration, and increases approximately linearly with the GC content of the DNA. 60 40 20 0 70 40 40 50 60% GC 30 50 60 70% GC 80 90 100 o Temperature / C 110 Double-stranded and single-stranded DNA differ in their optical absorption at 260 nm dA dG dU dC The conjugated π-electron systems of the purine & pyrimidine bases absorb strongly in the UV. nucleotides ssDNA dsDNA The The absorbance of double-stranded DNA (dsDNA) at 260 nm is less than that of either single-stranded DNA (ssDNA) or the free bases. This is called “hypochromism.” Hypochromism results from dipole-dipole interactions between neighboring bases The excited states of an interacting pair of molecules can be described as linear The combinations of the excited states of the individual molecules. In certain geometries, some of the absorption strength in the near-UV moves to bands at higher energies. increasing energy empty orbitals strong absorption band light filled orbitals individual base strong band near 2...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern