Mutation of a deacetylase that acts on H3K14Ac prevents the methylation at K9 because HDAC provide methylation sites for HMT.

TLS Online TPP Program

#Id: 2564

#Unit 13. Methods in Biology

The loop region of the beacon is designed to bind specifically to a target nucleic acid. Thus, in the presence of the target nucleic acid, the stem region of the beacon becomes separated, releasing the fluorophore from the quencher such that active fluorescence can be observed.

TLS Online TPP Program

#Id: 2565

#Unit 13. Methods in Biology

Molecular beacons consist of a stem (5–7 bp), and a loop (18–30 base pairs) and are labeled at the 5′ and 3′ ends by fluorophores and quenchers, respectively. 

TLS Online TPP Program

#Id: 4707

#Unit 13. Methods in Biology

From the four possible transitions (n!p*, p!p*, n!s*, s!s*), only two can be elicited with light from the UV/Vis spectrum for some biological molecules: n!p* and p!p*. The n!s* and s!s* transitions are

energetically not within the range of UV/Vis spectroscopy and require higher energies.

TLS Online TPP Program

#Id: 4708

#Unit 13. Methods in Biology

Molecular (sub-)structures responsible for interaction with electromagnetic radiation are called chromophores. 

TLS Online TPP Program

#Id: 4709

#Unit 13. Methods in Biology

In proteins, there are three types of chromophores relevant for UV/Vis spectroscopy:

• peptide bonds (amide bond);

• certain amino acid side chains (mainly tryptophan and tyrosine); and

• certain prosthetic groups and coenzymes (e.g. porphyrine groups such as in haem).

TLS Online TPP Program

#Id: 4710

#Unit 13. Methods in Biology

The presence of several conjugated double bonds in organic molecules results in an extended p-system of electrons which lowers the energy of the p* orbital through electron delocalisation.