Protein engineering, cofactor engineering and surface display
engineering to achieve whole-cell catalytic production of chondroitin
sulfate A
Abstract
Chondroitin sulfate A (CSA) is a valuable glycosaminoglycan that has
great market demand. However, current synthetic methods are limited by
requiring the expensive sulfate group donor
3′-phosphoadenosine-5′-phosphosulfate (PAPS) and inefficient enzyme
carbohydrate sulfotransferase 11 (CHST11). Herein, we report the design
and integration of the PAPS synthesis and sulfotransferase pathways to
realize whole-cell catalytic production of CSA. Using mechanism-based
protein engineering, we improved the thermostability and catalytic
efficiency of CHST11; its T m and half-life increased by
6.9°C and 3.5 h, respectively, and its specific activity increased
2.1-fold. Via cofactor engineering, we designed a dual cycle strategy of
regenerating ATP and PAPS to increase the supply of PAPS. Through
surface display engineering, we realized the outer membrane expression
of CHST11 and constructed a whole-cell catalytic system of CSA
production with a 89.5% conversion rate. This whole-cell catalytic
process provides a promising method for the industrial production of
CSA.