Molecular Imprinting of Complex Matrices at Localized Surface Plasmon Resonance Biosensors for Screening of Global Interactions of Polyphenols and Proteins

Molecular imprinting polymers (MIP) have been applied to capture and stabilize complex protein matrices at plasmonic sensor surfaces. Ultrathin MIP layers at the surface of gold nanodisks enable the label free quantification of global interactions of polyphenols with protein mixtures. Separate polyphenols (catechin, procyanidin B3- catechin dimer, and PGG-pentagalloyl glucose) give specific and different binding levels to the MIP supported saliva plasmonic sensor. The demonstrated biosensor has application to study bioavailability of polyphenols or evaluation of local retention of small drug molecules.info:eu-repo/semantics/publishedVersio

The human protein haptoglobin inhibits IsdH-mediated heme-sequestering by Staphylococcus aureus

Iron is an essential nutrient for all living organisms. Toacquire iron, many pathogens have developed elaborate systemsto steal it from their hosts. The iron acquisition system in theopportunistic pathogenStaphylococcus aureuscomprises nineproteins, called iron-regulated surface determinants (Isds). TheIsd components enableS. aureusto extract heme from hemo-globin (Hb), transport it into the bacterial cytoplasm, and ulti-mately release iron from the porphyrin ring. IsdB and IsdH actas hemoglobin receptors and are known to actively extract hemefrom extracellular Hb. To limit microbial pathogenicity duringinfection, host organisms attempt to restrict the availability ofnutrient metals at the host–pathogen interface. The humanacute phase protein haptoglobin (Hp) protects the host fromoxidative damage by clearing hemoglobin that has leaked fromred blood cells and also restricts the availability of extracellularHb-bound iron to invading pathogens. To investigate whetherHp serves an additional role in nutritional immunity through adirectinhibitionofIsdH-mediatedironacquisition,herewemea-sured heme extraction from the Hp–Hb complex by UV-visiblespectroscopy and determined the crystal structure of theHp–Hb–IsdH complex at 2.9 Å resolution. We found that Hpstrongly inhibits IsdH-mediated heme extraction and that Hpbinding prevents local unfolding of the Hb heme pocket, leavingIsdH unable to wrest the heme from Hb. Furthermore, we notedthat the Hp–Hb binding appears to trap IsdH in an initial statebefore heme transfer. Our findings provide insights into Hp-mediated IsdH inhibition and the dynamics of IsdH-mediatedheme extraction

Nanopattern Gradients for Cell Studies Fabricated Using Hole-Mask Colloidal Lithography

Culturing cells on gradient nanopatterns provides a useful tool to explore cellular adhesion to mimics of the extracellular matrix or screen for cellular responses to nanopatterns. A method is presented to fabricate complex gradient protein patterns based on hole-mask colloidal lithography, which can generate nanopatterns in multiple materials and of multiple shapes. Gradients of gold structures were functionalized to form gradients of protein nanopatterns of different shapes (bars, dot pairs, and rings), where a key parameter was systematically varied in each gradient. Cells were grown on vitronectin nanopatterns, showing differential adhesion (spread area/focal adhesion size) along the gradients

Purification, crystallization and preliminary X-ray diffraction of wild-type and mutant recombinant human transforming growth factor β-induced protein (TGFBIp)

Wild-type and mutant recombinant human transforming growth factor β-induced protein (TGFBIp) were cloned, purified and crystallized. Preliminary X-ray crystallography data were obtained from wild-type TGFBIp

Structural and functional implications of human transforming growth factor b-Induced protein, TGFBIp, in corneal dystrophies

A major cause of visual impairment, corneal dystrophies result from accumulation of protein deposits in the cornea. One of the proteins involved is transforming growth factor β-induced protein (TGFBIp), an extracellular matrix component that interacts with integrins but also produces corneal deposits when mutated. Human TGFBIp is a multi-domain 683-residue protein, which contains one CROPT domain and four FAS1 domains. Its structure spans ∼120 Å and reveals that vicinal domains FAS1-1/FAS1-2 and FAS1-3/FAS1-4 tightly interact in an equivalent manner. The FAS1 domains are sandwiches of two orthogonal four-stranded β sheets decorated with two three-helix insertions. The N-terminal FAS1 dimer forms a compact moiety with the structurally novel CROPT domain, which is a five-stranded all-β cysteine-knot solely found in TGFBIp and periostin. The overall TGFBIp architecture discloses regions for integrin binding and that most dystrophic mutations cluster at both molecule ends, within domains FAS1-1 and FAS1-4This study was funded in part by grants from Spanish (BFU2015-64487-R and MDM-2014-0435) and Catalan (2014SGR9) public agencies, as well as from the Danish Council for Independent Research, Medical Sciences (DFF-4004- 00471), the Lundbeck Foundation (R164-2013-15912), the Velux Foundation, and Fight for Sight, Denmark. T.G. acknowledges a ‘‘Juan de la Cierva’’ research contract (JCI-2012-13573) from the Spanish Ministry for Economy and Competitiveness. The Structural Biology Unit of IBMB is a ‘‘Marı´a de Maeztu’’ Unit of Excellence of the Spanish Ministry of Economy, Industry and Competitiveness. Funding for data collection was provided in part by ESRFPeer reviewe