Biology Reference
In-Depth Information
15
CHAPTER
Transforming Synthetic
Biology with Cell-Free
Systems
Arnaz Ranji
1
, Jeffrey C. Wu
2
, Bradley C. Bundy
2
and Michael C. Jewett
1
1
Northwestern University, Evanston, IL, USA
2
Brigham Young University, Provo, UT, USA
INTRODUCTION
Synthetic biology is a new approach for engineering biology by design. At its heart, this
emerging discipline seeks to make biology easier to engineer and to harness biology to serve
society. Already, this new paradigm for engineering biology is enabling a deeper
understanding of living systems and opening the way to sustainable and renewable energy
production, cost-effective and widely accessible programmable medicines, and new
solutions for environmental stewardship. While most synthetic biology efforts have focused
on engineering living organisms, the cell
277
s operating system and endogenous pathways pose
an obstacle to synthetic biology efforts. This is because the cell
'
s evolutionarily optimized
agenda for growth and adaptation are often at odds with the engineer
'
s objectives.
Additionally, the complexity of living cells is still beyond our comprehension, and serves as
a disadvantage to using living cells to develop synthetic biology applications. Cell-free
systems circumvent these obstacles, and are emerging as a powerful approach for harnessing
and expanding the capabilities of natural biological systems.
'
Over the last several years there has been tremendous development and innovation in the
growing, yet still small, field of cell-free synthetic biology. This chapter focuses on recent
developments and current applications in this field. We begin by defining cell-free biology
and its advantages. We then highlight existing applications in cell-free synthetic biology
from the nucleic acids to proteins to metabolites (
Fig. 15.1
). Finally, we consider challenges
and opportunities necessary to propel the field forward.
CELL-FREE BIOLOGY
Cell-free biology is the activation of complex biological processes without using intact,
living cells. Bypassing cell walls, this approach opens up a whole new biological world, one
without the need or ability to preserve DNA heritage.
1
Moreover, this approach enables one
to access and manipulate biology directly. In contrast to in vivo engineering efforts, this
direct relationship with biocatalytic enzymes provides the ability to focus metabolism on
the production of a single compound and removes physical barriers (allowing easy substrate
addition, product removal, and rapid sampling). Furthermore, avoiding competition
