title: Importance of Heat and Pressure for Solubilization of Recombinant Spider Silk Proteins in Aqueous Solution.
abstract: The production of recombinant spider silk proteins continues to be a key area of interest for a number of research groups. Several key obstacles exist in their production as well as in their formulation into useable products. The original reported method to solubilize recombinant spider silk proteins (rSSp) in an aqueous solution involved using microwaves to quickly generate heat and pressure inside of a sealed vial containing rSSp and water. Fibers produced from this system are remarkable in their mechanical ability and demonstrate the ability to be stretched and recover 100 times. The microwave method dissolves the rSSPs with dissolution time increasing with higher molecular weight constructs, increasing concentration of rSSPs, protein type, and salt concentration. It has proven successful in solvating a number of different rSSPs including native-like sequences (MaSp1, MaSp2, piriform, and aggregate) as well as chimeric sequences (FlAS) in varied concentrations that have been spun into fibers and formed into films, foams, sponges, gels, coatings, macro and micro spheres and adhesives. The system is effective but inherently unpredictable and difficult to control. Provided that the materials that can be generated from this method of dissolution are impressive, an alternative means of applying heat and pressure that is controllable and predictable has been developed. Results indicate that there are combinations of heat and pressure (135 °C and 140 psi) that result in maximal dissolution without degrading the recombinant MaSp2 protein tested, and that heat and pressure are the key elements to the method of dissolution.
authors.affiliation: Department of Biology, Utah State University, Logan, UT 84341, USA. justin.a.jones@usu.edu.
authors.forename: Justin A
authors.initials: JA
authors.lastname: Jones
authors.affiliation: Department of Biological Engineering, Utah State University, Logan, UT 84341, USA. tiharristh@gmail.com.
authors.forename: Thomas I
authors.initials: TI
authors.lastname: Harris
authors.affiliation: Department of Biology, Utah State University, Logan, UT 84341, USA. paula.oliveira@usu.edu.
authors.forename: Paula F
authors.initials: PF
authors.lastname: Oliveira
authors.affiliation: Department of Biology, Utah State University, Logan, UT 84341, USA. brianne.bell@aggiemail.usu.edu.
authors.forename: Brianne E
authors.initials: BE
authors.lastname: Bell
authors.affiliation: Department of Biology, Utah State University, Logan, UT 84341, USA. abood.alhabib@hotmail.com.
authors.forename: Abdulrahman
authors.initials: A
authors.lastname: Alhabib
authors.affiliation: Department of Biology, Utah State University, Logan, UT 84341, USA. randy.lewis@usu.edu.
authors.forename: Randolph V
authors.initials: RV
authors.lastname: Lewis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005349:Fibroins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D015870:Gene Expression; D006041:Goats; D006358:Hot Temperature; D008422:Materials Testing; D008872:Microwaves; D011312:Pressure; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D012995:Solubility; D012996:Solutions; D013112:Spiders / Q000502:physiology; D014867:Water / Q000737:chemistry
chemical_list: D011994:Recombinant Proteins; D012996:Solutions; D014867:Water; D005349:Fibroins
keywords: aqueous; fibers; heat; pressure; recombinant spider silk proteins; solvation