PMID- 21748239
OWN - NLM
STAT- MEDLINE
DCOM- 20120402
LR  - 20211020
IS  - 1573-4994 (Electronic)
IS  - 1053-0509 (Linking)
VI  - 21
IP  - 6
DP  - 2011 Nov
TI  - Localization and environment of tryptophans in different structural states of 
      concanavalin A.
PG  - 2123-32
LID - 10.1007/s10895-011-0913-4 [doi]
AB  - We have investigated the localization and environment of tryptophan residues in 
      different quaternary and conformational states (tetrameric, dimeric, monomeric 
      and unfolded) of metallized and demetallized concanavalin A (ConA) by selective 
      chemical modification, fluorescence, and phosphorescence. ConA has four 
      tryptophan residues (Trp 40, Trp 88, Trp 109 and Trp 182) per subunit. The 
      pattern of oxidation by N-bromosuccinimide (NBS) shows that NBS modifies, in 
      dimer, only Trp 182 which remains inaccessible in tetramer, two (Trp 88 along 
      with Trp 182) in monomer, all four in unfolded form in presence of EDTA, and 
      three (possibly Trp 40 along with Trp 88 and Trp 182) in unfolded form from 
      native or remetallized ConA. Utilizing wavelength-selective fluorescence 
      approach, we have observed a red edge excitation shift (REES) of 6-8 nm for 
      tetramer and dimer. A more pronounced REES (11 nm) is observed for oxidized 
      monomer compared to REES (3 nm) for unoxidized species. Acrylamide quenching 
      shows the Stern-Volmer constant (K(SV)) for dimer, monomer, unfolded ConA and 
      unfolded apo-ConA being 3.8, 5.2, 12.8, 14.0 M(-1), respectively. Phosphorescence 
      studies at 77 K give more structured spectra, with two (0,0) bands at 406.2 
      (weak) and 413.2 nm for tetramer. However, a single (0,0) band appears at 413.2 
      for dimer and 412.6 nm for monomer, while the (0,0) band of the oxidized monomer 
      is red shifted to 414.4 nm. These results may provide important insight into 
      subtlety of organization and environment of tryptophans in the context of folding 
      and structural studies of oligomeric proteins including lectins.
FAU - Mandal, Pritha
AU  - Mandal P
AD  - Department of Chemistry & Biochemistry, Presidency University, Kolkata 700 073, 
      India.
FAU - Mandal, Dipak K
AU  - Mandal DK
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20110712
PL  - Netherlands
TA  - J Fluoresc
JT  - Journal of fluorescence
JID - 9201341
RN  - 11028-71-0 (Concanavalin A)
RN  - 8DUH1N11BX (Tryptophan)
SB  - IM
MH  - Concanavalin A/*chemistry
MH  - Protein Conformation
MH  - Tryptophan/*chemistry
EDAT- 2011/07/13 06:00
MHDA- 2012/04/03 06:00
CRDT- 2011/07/13 06:00
PHST- 2011/04/14 00:00 [received]
PHST- 2011/07/04 00:00 [accepted]
PHST- 2011/07/13 06:00 [entrez]
PHST- 2011/07/13 06:00 [pubmed]
PHST- 2012/04/03 06:00 [medline]
AID - 10.1007/s10895-011-0913-4 [doi]
PST - ppublish
SO  - J Fluoresc. 2011 Nov;21(6):2123-32. doi: 10.1007/s10895-011-0913-4. Epub 2011 Jul 
      12.