Crystals of the apo form of the vitamin B12 and colicin receptor, BtuB, that diffract to 1.95 Å
have been grown by the membrane-based in meso technique. The structure of the protein …

The outer membranes of Gram-negative bacteria possess transport proteins essential for
uptake of scarce nutrients. In TonB-dependent transporters, a conserved sequence of seven …

Studies comparing the binding of genuine cobalamin (vitamin B12) to that of its natural or
synthetic analogues have long established increasing ligand specificity in the order …

Cobalamin (Cbl, vitamin B12) serves for two essential cofactors in mammals. The pathway
for its intestinal absorption, plasma transport, and cellular uptake uses cell surface receptors …

Abstract Cobalamin (Cbl, vitamin B12) is an essential micronutrient that is synthesized only
by bacteria. Mammals have developed a complex system for internalization of this vitamin …

BtuB, the cobalamin transporter from Escherichia coli, has been overexpressed, purified and
crystallized. The purified protein was solubilized in n-octyl tetraoxyethylene (C8E4) and was …

Successful macromolecular crystallography requires solution conditions that may alter the
conformational sampling of a macromolecule. Here, site-directed spin labeling is used to …

Gram-negative bacteria possess specialized active transport systems that function to
transport organometallic cofactors or carriers, such as cobalamins, siderophores, and …

Transport of vitamin B12 across the outer membrane of Escherichia coli, like that of iron-
siderophore complexes, is an active transport process requiring a specific outer membrane …

The structure and dynamics of the N-terminal and core regions of BtuB, an outer membrane
vitamin B12 transporter from Escherichia coli, were investigated by site-directed spin …