Molecular level design principle behind optimal sizes of photosynthetic LH2 complex: Taming disorder through cooperation of hydrogen bonding and quantum delocalization

Seogjoo Jang, Eva Rivera, Daniel Montemayor

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The light harvesting 2 (LH2) antenna complex from purple photosynthetic bacteria is an efficient natural excitation energy carrier with well-known symmetric structure, but the molecular level design principle governing its structure-function relationship is unknown. Our all-atomistic simulations of nonnatural analogues of LH2 as well as those of a natural LH2 suggest that nonnatural sizes of LH2-like complexes could be built. However, stable and consistent hydrogen bonding (HB) between bacteriochlorophyll and the protein is shown to be possible only near naturally occurring sizes, leading to significantly smaller disorder than for nonnatural ones. Extensive quantum calculations of intercomplex exciton transfer dynamics, sampled for a large set of disorder, reveal that taming the negative effect of disorder through a reliable HB as well as quantum delocalization of the exciton is a critical mechanism that makes LH2 highly functional, which also explains why the natural sizes of LH2 are indeed optimal.

Original languageEnglish (US)
Pages (from-to)928-934
Number of pages7
JournalJournal of Physical Chemistry Letters
Volume6
Issue number6
DOIs
StatePublished - Mar 19 2015
Externally publishedYes

Keywords

  • exciton
  • hydrogen bonding
  • light harvesting
  • optimal

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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