Presentation Title

Drivers of Tunable Iridescence in Squid Skin

Faculty Mentor

Dan Morse

Start Date

18-11-2017 12:30 PM

End Date

18-11-2017 1:30 PM

Location

BSC-Ursa Minor 70

Session

Poster 2

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Drivers of Tunable Iridescence in Squid Skin

Crístían V.R. Sharma, CCS Biology, University of California Santa Barbara

Robert Levenson, Dan E. Morse, Department of Molecular, Cellular, and Developmental Biology

Many cephalopod species employ iridescence both as a means of camouflage and communication. In particular, members of the Loliginid squid family display a mode of tunable iridescence that draws interest as a possible model for biologically inspired dynamically tunable photonic devices. This dynamic tunability is mediated by charge neutralization-induced assembly of the intrinsically unstructured cationic reflectin proteins. Reflectins are found within the lamellae of specialized Bragg reflector cells, which tunably reflect light across the visible spectrum. In order to understand the mechanisms controlling the tunable assembly of the reflectins, we studied assembly of wild type and mutant recombinant Doryteuthis opalescens reflectin A1 as a function of pH using dynamic light scattering (DLS) and native tryptophan fluorescence. Additionally, we have begun investigations into liquid-liquid phase separation as an avenue to reflectin assembly in vivo. To better investigate and understand this mechanism, we used cryo-TEM and bright field microscopy to visualize reflectin assemblies under near physiological conditions. These experiments have revealed relationships between reflectin assembly and neutralization of protein net charge density and screening of electrostatic interactions. These findings highlight the role of electrostatic neutralization as a driver of secondary structure emergence and subsequent hierarchical assembly in the reflectins, and help further develop a possible mechanism for the creation of biologically inspired photonic devices.

Summary of research results to be presented

We have observed an intermediary conformation for the transition between the oligomeric and multimeric forms of the intrinsically unstructured reflectin protein giving us further insight into the different conformational states of reflectin. Further, the truncation mutants have allowed us to narrow down on a specific part of the reflectin protein sequence that may be necessary for driving the dynamically tunable secondary structure emergence of this otherwise intrinsically unstructured protein.

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Nov 18th, 12:30 PM Nov 18th, 1:30 PM

Drivers of Tunable Iridescence in Squid Skin

BSC-Ursa Minor 70

Drivers of Tunable Iridescence in Squid Skin

Crístían V.R. Sharma, CCS Biology, University of California Santa Barbara

Robert Levenson, Dan E. Morse, Department of Molecular, Cellular, and Developmental Biology

Many cephalopod species employ iridescence both as a means of camouflage and communication. In particular, members of the Loliginid squid family display a mode of tunable iridescence that draws interest as a possible model for biologically inspired dynamically tunable photonic devices. This dynamic tunability is mediated by charge neutralization-induced assembly of the intrinsically unstructured cationic reflectin proteins. Reflectins are found within the lamellae of specialized Bragg reflector cells, which tunably reflect light across the visible spectrum. In order to understand the mechanisms controlling the tunable assembly of the reflectins, we studied assembly of wild type and mutant recombinant Doryteuthis opalescens reflectin A1 as a function of pH using dynamic light scattering (DLS) and native tryptophan fluorescence. Additionally, we have begun investigations into liquid-liquid phase separation as an avenue to reflectin assembly in vivo. To better investigate and understand this mechanism, we used cryo-TEM and bright field microscopy to visualize reflectin assemblies under near physiological conditions. These experiments have revealed relationships between reflectin assembly and neutralization of protein net charge density and screening of electrostatic interactions. These findings highlight the role of electrostatic neutralization as a driver of secondary structure emergence and subsequent hierarchical assembly in the reflectins, and help further develop a possible mechanism for the creation of biologically inspired photonic devices.