Biology subjects

Zheng, R. B.

Publications and source records attributed to Zheng, R. B..

2 recordsLinked to original sources

bioRxiv2020

Genetically Encoded, Multivalent Liquid Glycan Array (LiGA)

The Central Dogma of Biology does not allow for the study of glycans using DNA sequencing. We report a "Liquid Glycan Array" (LiGA) platform comprising a library of DNA barcoded M13 virions that display 30-1500 copies of glycans per phage. A LiGA is synthesized by acylation of phage pVIII protein with a dibenzocyclooctyne, followed by ligation of azido-modified glycans. Pulldown of the LiGA with lectins followed by deep sequencing of the barcodes in the bound phage decodes the optimal structure and density of the recognized glycans. The LiGA is target agnostic and can measure the glycan-binding profile of lectins such as CD22 on cells in vitro and immune cells in a live mouse. From a mixture of multivalent glycan probes, LiGAs identifies the glycoconjugates with optimal avidity necessary for binding to lectins on living cells in vitro and in vivo; measurements that cannot be performed with canonical glass slide-based glycan arrays. DedicationThe paper is dedicated to Laura L. Kiessling on the occasion of her 60th birthday.

biochemistry↗

bioRxiv2019

Cryo-EM Structures and Regulation of Arabinofuranosyltransferase AftD from Mycobacteria

Mycobacterium tuberculosis causes tuberculosis, a disease that kills over one million people each year. Its cell envelope is a common antibiotic target and has a unique structure due, in part, to two lipidated polysaccharides - arabinogalactan and lipoarabinomannan. Arabinofuranosyltransferase D (AftD) is an essential enzyme involved in assembling these glycolipids. We present the 2.9 [A] resolution structure of M. abscessus AftD determined by single particle cryo-electron microscopy. AftD has a conserved GT-C glycosyltransferase fold and three carbohydrate binding modules. Glycan array analysis shows that AftD binds complex arabinose glycans. Additionally, AftD is non-covalently complexed with an acyl carrier protein (ACP). 3.4 and 3.5 [A] structures of a mutant with impaired ACP binding reveal a conformational change that suggests the ACP may regulate AftD function. Using a conditional knock-out constructed in M. smegmatis, mutagenesis experiments confirm the essentiality of the putative active site and the ACP binding for AftD function.

biochemistry↗