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Biomolecules. 2017 Jun 13;7(2). pii: E43. doi: 10.3390/biom7020043.

Sequence Identification, Recombinant Production, and Analysis of the Self-Assembly of Egg Stalk Silk Proteins from Lacewing Chrysoperla carnea.

Neuenfeldt M1, Scheibel T2,3,4,5,6,7.

Author information

1
Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany. martin.neuenfeldt@bm.uni-bayreuth.de.
2
Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany. thomas.scheibel@bm.uni-bayreuth.de.
3
Forschungszentrum für Bio-Makromoleküle (BIOmac), Bayrisches Geoinstitut, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany. thomas.scheibel@bm.uni-bayreuth.de.
4
Bayreuther Materialzentrum (BayMat), Fakultät für Ingenieurwissenschaften, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany. thomas.scheibel@bm.uni-bayreuth.de.
5
Bayrisches Polymerinstitut (BPI), Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany. thomas.scheibel@bm.uni-bayreuth.de.
6
Bayreuther Zentrum für Kolloide und Grenzflächen (BZKG), Universität Bayreuth, Naturwissenschaften I, 95440 Bayreuth, Germany. thomas.scheibel@bm.uni-bayreuth.de.
7
Bayreuther Zentrum für Molekulare Biowissenschaften (BZMB), Universität Bayreuth, Naturwissenschaften I, 95440 Bayreuth, Germany. thomas.scheibel@bm.uni-bayreuth.de.

Abstract

Egg stalk silks of the common green lacewing Chrysoperla carnea likely comprise at least three different silk proteins. Based on the natural spinning process, it was hypothesized that these proteins self-assemble without shear stress, as adult lacewings do not use a spinneret. To examine this, the first sequence identification and determination of the gene expression profile of several silk proteins and various transcript variants thereof was conducted, and then the three major proteins were recombinantly produced in Escherichia coli encoded by their native complementary DNA (cDNA) sequences. Circular dichroism measurements indicated that the silk proteins in aqueous solutions had a mainly intrinsically disordered structure. The largest silk protein, which we named ChryC1, exhibited a lower critical solution temperature (LCST) behavior and self-assembled into fibers or film morphologies, depending on the conditions used. The second silk protein, ChryC2, self-assembled into nanofibrils and subsequently formed hydrogels. Circular dichroism and Fourier transform infrared spectroscopy confirmed conformational changes of both proteins into beta sheet rich structures upon assembly. ChryC3 did not self-assemble into any morphology under the tested conditions. Thereby, through this work, it could be shown that recombinant lacewing silk proteins can be produced and further used for studying the fiber formation of lacewing egg stalks.

KEYWORDS:

circular dichroism; genome analysis; insect silk; qPCR; recombinant proteins; self-assembly; transcript variants

PMID:
28608840
PMCID:
PMC5485732
DOI:
10.3390/biom7020043
[Indexed for MEDLINE]
Free PMC Article

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