Chang-Ye Hui1, Yan Guo2, Xue-Qin Yang2, Wen Zhang2, Xian-Qing Huang2. 1. Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, 518020, China. hcy_sypu@hotmail.com. 2. Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, 518020, China.
Abstract
OBJECTIVES: To improve the Pb2+ biosorption capacity of the potential E. coli biosorbent, a putative Pb2+ binding domain (PbBD) derived from PbrR was efficiently displayed on to the E. coli cell surface. RESULTS: The PbBD was obtained by truncating the N-terminal DNA-binding domain and C-terminal redundant amino acid residues of the Pb2+-sensing transcriptional factor PbrR. Whole-cell sorbents were constructed with the full-length PbrR and PbBD of PbrR genetically engineered onto the surface of E. coli cells using Lpp-OmpA as the anchor. Followed by a 1.71-fold higher display of PbBD than PbrR, the presence of PbBD on the surface of E. coli cells enabled a 1.92-fold higher Pb2+ biosorption than that found in PbrR-displayed cells. Specific Pb2+ binding via PbBD was the same as Pb2+ binding via the full-length PbrR, with no observable decline even in the presence of Zn2+ and Cd2+. CONCLUSIONS: Since surface-engineered E. coli cells with PbBD increased the Pb2+ binding capacity and did not affect the adsorption selectivity, this suggests that surface display of the metal binding domain derived from MerR-like proteins may be used for the bioremediation of specific toxic heavy metals.
OBJECTIVES: To improve the Pb2+ biosorption capacity of the potential E. coli biosorbent, a putative Pb2+ binding domain (PbBD) derived from PbrR was efficiently displayed on to the E. coli cell surface. RESULTS: The PbBD was obtained by truncating the N-terminal DNA-binding domain and C-terminal redundant amino acid residues of the Pb2+-sensing transcriptional factor PbrR. Whole-cell sorbents were constructed with the full-length PbrR and PbBD of PbrR genetically engineered onto the surface of E. coli cells using Lpp-OmpA as the anchor. Followed by a 1.71-fold higher display of PbBD than PbrR, the presence of PbBD on the surface of E. coli cells enabled a 1.92-fold higher Pb2+ biosorption than that found in PbrR-displayed cells. Specific Pb2+ binding via PbBD was the same as Pb2+ binding via the full-length PbrR, with no observable decline even in the presence of Zn2+ and Cd2+. CONCLUSIONS: Since surface-engineered E. coli cells with PbBD increased the Pb2+ binding capacity and did not affect the adsorption selectivity, this suggests that surface display of the metal binding domain derived from MerR-like proteins may be used for the bioremediation of specific toxic heavy metals.
Entities:
Keywords:
Bioadsorption; Lead; Metal binding domain; PbrR; Surface display