Despite rising interest in the engineering of polysaccharide-based biomaterials, relatively little is known about how plant hemicelluloses can be built and tailored in non-plant cell factories. Pichiapastoris is a promising host to study cellulose synthase-like A (CSLA; heteromannan synthases) and CSLC (xyloglucan synthase) activities but the functions of specific protein motifs and the impact of their products remain unclear. Here, we used a Golden Gate-based system to assemble chimeric CSL enzymes and optimize yeast cultivation to rapidly produce hemicellulose in mg scale.
Interestingly, prolonged expression of a konjac AkCSLA3 glucomannan synthase was toxic to yeast cells, but this impairment was restored by swapping its C-terminal region with that of an Arabidopsis AtCSLA2 mannan synthase. Additional chimeras exceeded the yields of the native enzymes. Overall, cell size was increased or decreased depending on the CSLA sequences used.
Yeast containing plant-like polysaccharides could be viewed as tunable biological capsules for further metabolic engineering studies. Sensitive macromolecules such as therapeutic proteins can be protected by encapsulation in non-toxic plant polysaccharides and Pichia cells are attractive hosts for recombinant protein production. Therefore, our strategy provides basic insight into matrix polysaccharide biosynthesis and could also be used to encapsulate valuable cargo.
We are happy to welcome Sooyun Lee and Tilman Jacob to the Designer Glycans lab. Sooyun first joined us for an internship in February to evaluate fluorescent reporters in Pichia pastoris. She will now start her MSc research thesis on secreting proteins from yeast to modify extracellular glycans.
Tilman is a first-year MSc student at the Martin Luther University, who will initially work as a research assistant. Having previously worked with G-protein-coupled receptors in human cell lines, he is not afraid to investigate some our of membrane-bound glycosyltransferases.
Debora Gasperini, Katharina Bürstenbinder and Catalin Voiniciuc are co-organizing the Leibniz Plant Biochemistry Symposium 2021. This annual conference will be focused on Plant Cell Walls this year, and will be held as an online event for the first time.
We have an exciting speaker line-up and there will be free registration for participants from around the world. Space is limited, so don’t miss out.
We are happy to have contributed to a new publication that appeared in Science Advances on the February 10. This study unveils how jasmonate signaling is initiated in the korrigan1 (kor1) cellulose-deficient mutant, and multiple ways in which it can be complemented. The work was lead by Stefan Mielke in Debora Gasperini’s research group at IPB Halle.
Catalin Voiniciuc performed the cell wall analyses, and would like to acknowledge the valuable technical assistance of Christine Wagner and Bo Yang. The Science Advances study was originally available as a pre-print:
February also marks the release of a correction to the Voiniciuc et al. (2018) Plant Physiology study of pectin biosynthetic enzymes. Unfortunately, there was an accidental mix-up of GAUT11 and another GAUT protein expressed at the same time. Catalin would like to thank the co-authors for reporting the problem affecting Figure 5 and Supplemental Figure 4A, and repeating the experiments. The corrigendum has addressed this issue and shows that the original results and conclusions that GAUT11 is a galacturonosyltransferase (GalAT) that elongates homogalacturonan (HG) are unaffected.
Our revised manuscript on the roles of branched xylan and heteromannan (previously available as a preprint) in controlling seed mucilage properties and early growth in salt stress has now been peer-reviewed.