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SUMMARY:Influence of solvent effects on Qy transitions in chlorophyll
DTSTART;VALUE=DATE-TIME:20110714T150000Z
DTEND;VALUE=DATE-TIME:20110714T170000Z
DTSTAMP;VALUE=DATE-TIME:20260714T164726Z
UID:indico-contribution-4915@events.saip.org.za
DESCRIPTION:Speakers: Jacoba Smit (CSIR Biosciences\, Pretoria\, South Afr
 ica)\nThe most abundant and efficient light harvesting\, energy transfer a
 nd transduction systems are found in nature within the process of photosyn
 thesis. Although the processing sequences of an absorbed solar photon in t
 he photosynthetic apparatus have been deciphered\, the underlying physical
  basis of photosynthesis is not well understood yet. Our research aims to 
 contribute to this understanding by characterising the level of organisati
 on of the Light Harvesting II complexes (LHCII) and energy transfer system
 s when incorporated into artificial vesicles called PheroidTM. LHCII was e
 xtracted from spinach leaves in a 20 mM Tricine buffer to stabilise the pr
 oteins. Raman\, FTIR and absorbance spectra of samples were compared. The 
 Qy transitions of chlorophyll in the red (Qy) region of the absorption spe
 ctra appears to red-shift by 3.5 – 5.5 nm\; indicating a possible change
  in organisation of the light harvesting system after incorporation into t
 he PheroidTM. These shifts however could also be interpreted as bathochrom
 ic solvent effects due to the Tricine buffer. The objectives of this study
  were (1) to investigate whether the red-shifts were due to the Tricine bu
 ffer and (2) if so\, whether the alternative use of a 20 mM K2HPO4 / KH2PO
 4 buffer could eliminate the bathochromic solvent effects. The Tricine buf
 fer was dialysed out of the samples directly into a 20 mM K2HPO4 / KH2PO4 
 buffer to prevent denaturing of the LHCII proteins. Preliminary results in
 dicated a lessening of the bathochromic effects with the K2HPO4 / KH2PO4 b
 uffer.\n\nhttps://events.saip.org.za/event/7/contributions/4915/
LOCATION: Asteria
URL:https://events.saip.org.za/event/7/contributions/4915/
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