The last residue of the protein (tail) is Tryptophan, and the first residue (head) is labeled with IAEDANS acceptor. Estimate the length of the protein (head to tail) if the efficiency of RET measures at 0.01 Please show step by step and how to get the 34.014 number **Table 20.2: Values of R₀ for some donor–acceptor pairs**| Donor | Acceptor | R₀/nm ||------------|----------|-------|| Naphthalene | Dansyl | 2.2 || Dansyl | ODR | 4.3 || Pyrene | Coumarin | 3.9 || IAEDANS | FITC | 4.9 || Tryptophan | IAEDANS | 2.2 || Tryptophan | Haem | 2.9 |**Abbreviations:**- **Dansyl:** 5-dimethylamino-1-naphthalenesulfonic- **FITC:** fluorescein-5-isothiocyanate- **IAEDANS:** 5-(((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid- **ODR:** octadecyl-rhodamineThe table presents donor–acceptor pairs, showing their respective Förster distance (R₀) values, which indicate the efficiency of energy transfer processes between the pairs. These values are measured in nanometers (nm), and they are crucial in fields such as fluorescence resonance energy transfer (FRET) analysis.

Fluorescence Resonance Energy Transfer (FRET) or simply RET is a technique used to calculate the distance between 2 points in a biochemical system like a protein. FRET analysis requires a fluorescent donor and a fluorescent acceptor . Here a fluorescent donor absorbs a specific wavelength of light and then emits a different wavelength of light. The fluorescent acceptor absorbs this exact wavelength of light emitted by the fluorescent donor and then emits a different wavelength of light. The efficiency at which this fluorescent acceptor absorbs the wavelength of light emitted by the fluorescent donor decreases as the distance between the fluorescent donor and the fluorescent acceptor increases. In the question given, tryptophan is the fluorescent donor and IAEDANS is the fluorescent acceptor.Efficiency of RET =R06R06 + r6here; 'R0' is the distance between donor and acceptor at 50% efficiency 'r' is the actual distance between donor and acceptor.R0 for tryptophan as donor and IAEDAN as acceptor is 2.2nm in thetable given.0.01=2.2 nm62.2 nm6 + r6 r = 4.732 nm So, the distance between tryptophan and IAEDANS is 4.732 nm. If the protein in question is assumed to be linear, then the length of protein (head to tail) is 4.732 nm . Note : the length of the protein (head to tail) is 4.732nm and not associated with the number 34.014 . This answer is valid with the assumption that the protein is linear. We take this assumption as no information on the particular shape of the protein is provided in question.