Please use this identifier to cite or link to this item: https://doi.org/10.1099/mic.0.25942-0
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dc.titleIdentification of the essential histidine residue for high-affinity binding of AlbA protein to albicidin antibiotics
dc.contributor.authorWeng, L.-X.
dc.contributor.authorXu, J.-L.
dc.contributor.authorLi, Q.
dc.contributor.authorBirch, R.G.
dc.contributor.authorZhang, L.-H.
dc.date.accessioned2014-10-27T08:48:30Z
dc.date.available2014-10-27T08:48:30Z
dc.date.issued2003-02-01
dc.identifier.citationWeng, L.-X., Xu, J.-L., Li, Q., Birch, R.G., Zhang, L.-H. (2003-02-01). Identification of the essential histidine residue for high-affinity binding of AlbA protein to albicidin antibiotics. Microbiology 149 (2) : 451-457. ScholarBank@NUS Repository. https://doi.org/10.1099/mic.0.25942-0
dc.identifier.issn13500872
dc.identifier.urihttp://scholarbank.nus.edu.sg/handle/10635/102467
dc.description.abstractThe albA gene from Klebsiella oxytoca encodes a protein that binds albicidin phytotoxins and antibiotics with high affinity. Previously, it has been shown that shifting pH from 6 to 4 reduces binding activity of AlbA by about 30 %, indicating that histidine residues might be involved in substrate binding. In this study, molecular analysis of the albA coding region revealed sequence discrepancies with the albA sequence reported previously, which were probably due to sequencing errors. The albA gene was subsequently cloned from K. oxytoca ATCC 13182T to establish the revised sequence. Biochemical and molecular approaches were used to determine the functional role of four histidine residues (His78, His125, His141 and His189) in the corrected sequence for AlbA. Treatment of AlbA with diethyl pyrocarbonate (DEPC), a histidine-specific alkylating reagent, reduced binding activity by about 95 %. DEPC treatment increased absorbance at 240-244 nm by an amount indicating conversion to N-carbethoxyhistidine of a single histidine residue per AlbA molecule. Pretreatment with albicidin protected AlbA against modification by DEPC, with a 1:1 molar ratio of albicidin to the protected histidine residues. Based on protein secondary structure and amino acid surface probability indices, it is predicted that His125 might be the residue required for albicidin binding. Mutation of His125 to either alanine or leucine resulted in about 32 % loss of binding activity, and deletion of His125 totally abolished binding activity. Mutation of His125 to arginine and tyrosine had no effect. These results indicate that His125 plays a key role either in an electrostatic interaction between AlbA and albicidin or in the conformational dynamics of the albicidin-binding site.
dc.description.urihttp://libproxy1.nus.edu.sg/login?url=http://dx.doi.org/10.1099/mic.0.25942-0
dc.sourceScopus
dc.typeReview
dc.contributor.departmentBIOLOGICAL SCIENCES
dc.description.doi10.1099/mic.0.25942-0
dc.description.sourcetitleMicrobiology
dc.description.volume149
dc.description.issue2
dc.description.page451-457
dc.description.codenMROBE
dc.identifier.isiut000181006200017
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