Part Collection

Part Collection

The aim of our project, Ubenefactrix, is to develop a novel self-assembled biomaterial and fabricate it into a multi-functional fiber by incorporating different functional proteins, in an attempt to be applied in various fields in the future. This year, we not only designed Ubx, but also identified its dityrosine containing domain to make a new short peptide that contains the same property of the original Ubx protein, self-assembly by tyrosine cross linking.

Basic Parts

Ubx (Part:BBa_K4377000)

This year, we created a new part, Ultrabithorax (Ubx), which is a homeotic protein from Drosophila melanogaster. In addition to its well-known characteristic as a transcription factor, the unique in vitro features of Ubx have given it the advantages over many protein-based biomaterials.[1]

First, Ubx is biocompatible, biodegradable and non-immunogenetic. Those protein properties have highlighted their possible use in biomedicine. Second, Ubx possesses the ability to self-assemble into nanoscale fiber by forming crosslinking dityrosine bonds. Dityrosine containing motifs are the domains contributing to most self-assembly.[2] Lastly, a study shows that Ubx can be readily functionalized with other proteins and retain its structure stability and mechanical properties afterwards.[3]

Figure 1.Basic part K4377000

Composite Parts

Ubx (Part:BBa_K4377006)

We construct the composite part of Ubx with a constitutive promoter, RBS (B0034) and His-tag.

Figure 2.Composite part K4377006. This composite part contains constitutive promoter, RBS, and Ubx protein.

Y167-mRFP-Y240 (Part:BBa_K4377009)

In our experiments cycle 1, the expression of Ubx in Escherichia coli (E. coli) is under expectation. Thus, we developed approaches to narrow down to Y167 and Y240 dityrosine containing domains among Ubx sequences, as dityrosine cross-linkings are evidenced to drive the assembly of proteins and peptides. We engineered functional protein mRFP with Y167 Y240 short peptides in the attempt to verify the self-assembly function. Through functional tests, we had successfully achieved our goal of creating the biomaterial that contains self-assembling ability and preserving the function of functional protein fusion with them.

Figure 3.Composite part K4377009. This composite part contains a constitutive promoter, RBS,10x His tag, mRFP, and two functional domains of Ubx protein.


  1. Pavlopoulos, A., & Akam, M. (2011, February 15). Hox gene ultrabithorax regulates distinct sets of target genes at successive stages of drosophila haltere morphogenesis. Proceedings of the National Academy of Sciences of the United States of America.
  2. Alexandra M. Greer, Zhao Huang, Ashley Oriakhi(2009, March 18). The Drosophila Transcription Factor Ultrabithorax Self-Assembles into Protein-Based Biomaterials with Multiple Morphologies Biomacromolecules 2009 10 (4),829-837
  3. Tsai, S.-P., Howell, D.W., Huang, Z., Hsiao, H.-C., Lu, Y., Matthews, K.S., Lou, J. and Bondos, S.E. (2015), The Effect of Protein Fusions on the Production and Mechanical Properties of Protein-Based Materials. Adv. Funct. Mater., 25: 1442-1450