Task 3 12 April 2017
CALCULATION OF A DISTANCE FROM FRET DATA
The protein human serum albumin (HSA) contains
a single tryptophan residue at position 214. HSA
was labeled with an anthraniloyl group placed
covalently on cysteine 34 (Fig.1). Emission spectra
of the labeled and unlabeled HSA are shown in Fig.
2. The Förster distance for Trp to anthraniloyl
transfer is listed in Table 2 by your name. Use the
values from Table 1 derived from emission spectra
in Fig. 2 to calculate the Trp to anthraniloyl
distance.
Table 1
1. What is the transfer efficiency E between Trp 214 and anthraniloyl E for
modified HSA? Calculate the E value to two decimal places.
2. What is the distance Trp 214 and anthraniloyl cysteine 34 calculated based on
fluorescence resonance energy transfer?
Indicate the distance value in Angstrems (Å) with precision to one decimal place.
Send me your answer via email. Correct answer = 1 point.
Table 2
R0
(Å)
1 Akhmetgalieva, Valentina 28.0
2 Alispahic, Elma 27.5
3 Atatri, Sura S. M. 29.1
4 Janovič, Tomáš 31.3
5 Lobello, Cosimo 30.3
This task was prepared base on Problem 1.6 on page 25 in Principles of fluorescence
spectroscopy (2006) book of Prof. Lakowicz.
relative fluorescence
λ (340nm) λ (408nm)
HSA 0.546 0.091
mod HSA 0.202 0.687Fig. 2
Fig. 1