'The medicine is not for sale': Practices of traditional healers in snakebite envenoming in Ghana.

Background: Snakebite envenoming is a medical emergency which is common in many tropical lower- and middle-income countries. Traditional healers are frequently consulted as primary care-givers for snakebite victims in distress. Traditional healers therefore present a valuable source of information about how snakebite is perceived and handled at the community level, an understanding of which is critical to improve and extend snakebite-related healthcare.

Structural basis of nanobody-mediated blocking of BtuF, the cognate substrate-binding protein of the Escherichia coli vitamin B12 transporter BtuCD.

Bacterial ABC importers catalyze the uptake of essential nutrients including transition metals and metal-containing co-factors. Recently, an IgG antibody targeting the external binding protein of the Staphylococcus aureus Mn(II) ABC importer was reported to inhibit transport activity and reduce bacterial cell growth. We here explored the possibility of using alpaca-derived nanobodies to inhibit the vitamin B12 transporter of Escherichia coli, BtuCD-F, as a model system by generating nanobodies against the periplasmic binding protein BtuF.

Conformational Change of a Tryptophan Residue in BtuF Facilitates Binding and Transport of Cobinamide by the Vitamin B12 Transporter BtuCD-F.

BtuCD-F is an ABC transporter that mediates cobalamin uptake into Escherichia coli. Early in vivo data suggested that BtuCD-F might also be involved in the uptake of cobinamide, a cobalamin precursor. However, neither was it demonstrated that BtuCD-F indeed transports cobinamide, nor was the structural basis of its recognition known.

On the efficiency of NHS ester cross-linkers for stabilizing integral membrane protein complexes.

We have previously presented a straightforward approach based on high-mass matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) to study membrane proteins. In addition, the stoichiometry of integral membrane protein complexes could be determined by MALDI-MS, following chemical cross-linking via glutaraldehyde. However, glutaraldehyde polymerizes in solution and reacts nonspecifically with various functional groups of proteins, limiting its usefulness for structural studies of protein complexes.

Structure of AMP-PNP-bound BtuCD and mechanism of ATP-powered vitamin B12 transport by BtuCD-F.

The reaction mechanism of BtuCD-F-catalyzed vitamin B12 transport into Escherichia coli is currently unclear. Here we present the structure of the last missing state in the form of AMP-PNP-bound BtuCD, trapped by a disulfide cross-link. Our structural and biochemical data allow a consistent mechanism to be formulated, thus rationalizing the roles of substrate, ATP and substrate-binding protein.

Buruli ulcer control in a highly endemic district in Ghana: role of community-based surveillance volunteers.

Buruli ulcer (BU) is an infectious skin disease that occurs mainly in West and Central Africa. It can lead to severe disability and stigma because of scarring and contractures. Effective treatment with antibiotics is available, but patients often report to the hospital too late to prevent surgery and the disabling consequences of the disease.

High-mass matrix-assisted laser desorption ionization-mass spectrometry of integral membrane proteins and their complexes.

Analyzing purified membrane proteins and membrane protein complexes by mass spectrometry has been notoriously challenging and required highly specialized buffer conditions, sample preparation methods, and apparatus. Here we show that a standard matrix-assisted laser desorption/ionization (MALDI) protocol, if used in combination with a high-mass detector, allows straightforward mass spectrometric measurements of integral membrane proteins and their complexes, directly following purification in detergent solution. Molecular weights can be determined precisely (mass error ≤ 0.

Structure of AMP-PNP-bound vitamin B12 transporter BtuCD-F.

The ATP-binding cassette (ABC) transporter BtuCD mediates the uptake of vitamin B(12) across the inner membrane of Escherichia coli. Previous structures have shown the conformations of apo states, but the transport mechanism has remained unclear. Here we report the 3.

Asymmetric states of vitamin B₁₂ transporter BtuCD are not discriminated by its cognate substrate binding protein BtuF.

BtuCD is an ABC transporter catalyzing the uptake of vitamin B₁₂ across the Escherichia coli inner membrane. A previously reported X-ray structure of BtuCD in complex with the periplasmic vitamin B₁₂-binding protein BtuF revealed asymmetry of the transmembrane BtuC subunits. The functional relevance of this asymmetry has remained uncertain.