PMID- 15648086
OWN - NLM
STAT- MEDLINE
DCOM- 20050512
LR  - 20131121
IS  - 0006-3525 (Print)
IS  - 0006-3525 (Linking)
VI  - 77
IP  - 6
DP  - 2005 Apr 15
TI  - Effect of ionic strength on the organization and dynamics of tryptophan residues 
      in erythroid spectrin: a fluorescence approach.
PG  - 325-34
AB  - The ionic strength of the medium plays an important role in the structure and 
      conformation of erythroid spectrin. The spectrin dimer is a flexible rod at 
      physiological ionic strength. However, lower ionic strength results in elongation 
      and rigidification (stiffening) of spectrin as shown earlier by electron 
      microscopy and hydrodynamic studies. The ionic strength induced structural 
      transition does not involve any specific secondary structural changes. In this 
      article, we have used a combination of fluorescence spectroscopic approaches that 
      include red edge excitation shift (REES), fluorescence quenching, time-resolved 
      fluorescence measurements, and chemical modification of the spectrin tryptophans 
      to assess the environment and dynamics of tryptophan residues of spectrin under 
      different ionic strength conditions. Our results show that while REES, 
      fluorescence anisotropy, lifetime, and chemical modification of spectrin 
      tryptophans remain unaltered in low and high ionic strength conditions, quenching 
      of tryptophan fluorescence by the aqueous quencher acrylamide (but not the 
      hydrophobic quencher trichloroethanol) and resonance energy transfer to a 
      dansyl-labeled fatty acid show differences in tryptophan environment. These 
      results, which report tertiary structural changes in spectrin upon change in 
      ionic strength, are relevant in understanding the molecular details underlying 
      the conformational flexibility of spectrin.
CI  - Copyright 2005 Wiley Periodicals, Inc.
FAU - Kelkar, Devaki A
AU  - Kelkar DA
AD  - Centre for Cellular and Molecular Biology, Hyderabad 500 007, India.
FAU - Chattopadhyay, Amitabha
AU  - Chattopadhyay A
FAU - Chakrabarti, Abhijit
AU  - Chakrabarti A
FAU - Bhattacharyya, Malyasri
AU  - Bhattacharyya M
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Biopolymers
JT  - Biopolymers
JID - 0372525
RN  - 12634-43-4 (Spectrin)
RN  - 8DUH1N11BX (Tryptophan)
SB  - IM
MH  - Animals
MH  - Erythrocyte Membrane/chemistry
MH  - Goats
MH  - Kinetics
MH  - Osmolar Concentration
MH  - Spectrin/*chemistry/isolation & purification
MH  - Spectrometry, Fluorescence
MH  - Tryptophan/*analysis
EDAT- 2005/01/14 09:00
MHDA- 2005/05/13 09:00
CRDT- 2005/01/14 09:00
PHST- 2005/01/14 09:00 [pubmed]
PHST- 2005/05/13 09:00 [medline]
PHST- 2005/01/14 09:00 [entrez]
AID - 10.1002/bip.20233 [doi]
PST - ppublish
SO  - Biopolymers. 2005 Apr 15;77(6):325-34. doi: 10.1002/bip.20233.