Amphiphilic, hydrophilic, or hydrophobic synthetic bacteriochlorins in biohybrid light-harvesting architectures: Consideration of molecular designs

Jianbing Jiang, Kanumuri Ramesh Reddy, M. Phani Pavan, Elisa Lubian, Michelle A. Harris, Jieying Jiao, Dariusz M. Niedzwiedzki, Christine Kirmaier, Pamela S. Parkes-Loach, Paul A. Loach, David F. Bocian, Dewey Holten, Jonathan S. Lindsey*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Biohybrid light-harvesting architectures can be constructed that employ native-like bacterial photosynthetic antenna peptides as a scaffold to which synthetic chromophores are attached to augment overall spectral coverage. Synthetic bacteriochlorins are attractive to enhance capture of solar radiation in the photon-rich near-infrared spectral region. The effect of the polarity of the bacteriochlorin substituents on the antenna self-assembly process was explored by the preparation of a bacteriochlorin-peptide conjugate using a synthetic amphiphilic bacteriochlorin (B1) to complement prior studies using hydrophilic (B2, four carboxylic acids) or hydrophobic (B3) bacteriochlorins. The amphiphilic bioconjugatable bacteriochlorin B1 with a polar ammonium-terminated tail was synthesized by sequential Pd-mediated reactions of a 3,13-dibromo-5-methoxybacteriochlorin. Each bacteriochlorin bears a maleimido-terminated tether for attachment to a cysteine-containing analog of the Rhodobacter sphaeroides antenna β-peptide to give conjugates β-B1, β-B2, and β-B3. Given the hydrophobic nature of the β-peptide, the polarity of B1 and B2 facilitated purification of the respective conjugate compared to the hydrophobic B3. Bacteriochlorophyll a (BChl a) associates with each conjugate in aqueous micellar media to form a dyad containing two β-peptides, two covalently attached synthetic bacteriochlorins, and a datively bonded BChl-a pair, albeit to a limited extent for β-B2. The reversible assembly/disassembly of dyad (β-B2/BChl)2 was examined in aqueous detergent (octyl glucoside) solution by temperature variation (15-35 °C). The energy-transfer efficiency from the synthetic bacteriochlorin to the BChl-a dimer was found to be 0.85 for (β-B1/BChl)2, 0.40 for (β-B2/BChl)2, and 0.85 for (β-B3/BChl)2. Thus, in terms of handling, assembly and energy-transfer efficiency taken together, the amphiphilic design examined herein is more attractive than the prior hydrophilic or hydrophobic designs.

Original languageEnglish (US)
Pages (from-to)187-202
Number of pages16
JournalPhotosynthesis Research
Issue number2
StatePublished - Nov 2014


  • Bacteriochlorin
  • Bacteriochlorophyll
  • Bioconjugate
  • Dyad
  • Energy transfer
  • Light harvesting
  • Photosynthetic antenna
  • Self-assembly

ASJC Scopus subject areas

  • Biochemistry
  • Plant Science
  • Cell Biology


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