Biochemical applications of surface-enhanced infrared absorption spectroscopy

An overview is presented on the application of surface-enhanced infrared absorption (SEIRA) spectroscopy to biochemical problems. Use of SEIRA results in high surface sensitivity by enhancing the signal of the adsorbed molecule by approximately two orders of magnitude and has the potential to enable new studies, from fundamental aspects to applied sciences. This report surveys studies of DNA and nucleic acid adsorption to gold surfaces, development of immunoassays, electron transfer between metal electrodes and proteins, and protein–protein interactions. Because signal enhancement in SEIRA uses surface properties of the nano-structured metal, the biomaterial must be tethered to the metal without hampering its functionality. Because many biochemical reactions proceed vectorially, their functionality depends on proper orientation of the biomaterial. Thus, surface-modification techniques are addressed that enable control of the proper orientation of proteins on the metal surface. [Figure: see text

Long distance electron transfer in cytochrome c oxidase immobilised on electrodes. A surface enhanced resonance Raman spectroscopic study

Cytochrome c oxidase was tethered to a functionalised Ag electrode via a histidine-tag on the C-terminus of subunit I or II and embedded in a phospholipid bilayer. The uniformly oriented membrane-bound proteins were studied by surface enhanced resonance Raman spectroscopy (SERRS) that reveals preservation of the native structures of the heme a and heme a(3) sites. On the basis of time-dependent SERRS measurements, the rate constant for the heterogeneous electron transfer to heme a was determined to be 0.002 s(-1) independent of the enzyme orientation and the overpotential. Taking into account that the electrode-to-heme a distance is larger than 50 A, these findings suggest an electron hopping mechanism in which the Cu(A) center is not involved. Electrochemical reduction is restricted to heme a whereas electron transfer from heme a to heme a(3), which in solution occurs on the nanosecond time scale, is drastically slowed down. It may be that the network of cooperativities that links intramolecular electron transfer and proton translocation is perturbed in the immobilised enzyme, possibly due to the effect of the interfacial electric field

Molluscs of the Bukovske vrchy Mts in the Slovakian part of the Vychodne Karpaty Biosphere Reserve

91 mollusc species were recorded from 92 sites in the Bukovské vrchy Mts (Slovakia) as a result of the recent malacological research, combined with earlier published and unpublished data. The most important communities of predominantly East Carpathian species occur throughout the deciduous woodlands dominated by beech. The mollusc communities are characterised by low numbers of individuals dispersed over large areas. Rich malacocoenoses are confined to scattered favourable habitats, such as well vegetated base-rich seepages, landslide scars and water-logged depressions, as well as at fresh calcareous outcrops or screes. A detailed snail succession from Holocene slope sediments at the Krivoštianka (Humenské vrchy Mts) provides the most complete record from the Slovak East Carpathians and is the most detailed yet published from this region. The mollusc succession differs from the standard faunal developmental pattern of Central Europe due to the absence of a considerable number of common Central European species, whose succession is well known at present

Direct Electron Transfer between an Electrode and Cytochrome c Oxidase Immobilised in a Novel Biomimetic Lipid Membrane

Membrane-bound cytochrome c oxidase was attached to an electrode via a His-tag linker and studied by surface enhanced resonance Raman spectroscopy, demonstrating intact redox site structures and electron transfer between the electrode and the immobilized enzyme

Cancer Cell Response to Anthracyclines Effects: Mysteries of the Hidden Proteins Associated with These Drugs

A comprehensive proteome map of T-lymphoblastic leukemia cells and its alterations after daunorubicin, doxorubicin and mitoxantrone treatments was monitored and evaluated either by paired comparison with relevant untreated control and using multivariate classification of treated and untreated samples. With the main focus on early time intervals when the influence of apoptosis is minimized, we found significantly different levels of proteins, which corresponded to 1%–2% of the total amount of protein spots detected. According to Gene Ontology classification of biological processes, the highest representation of identified proteins for all three drugs belong to metabolic processes of proteins and nucleic acids and cellular processes, mainly cytoskeleton organisation and ubiquitin-proteasome pathway. Importantly, we observed significant proportion of changes in proteins involved in the generation of precursor metabolites and energy typical for daunorubicin, transport proteins participating in response to doxorubicin and a group of proteins of immune system characterising response to mitoxantrone. Both a paired comparison and the multivariate evaluation of quantitative data revealed daunorubicin as a distinct member of the group of anthracycline/anthracenedione drugs. A combination of identified drug specific protein changes, which may help to explain anti-cancer activity, together with the benefit of blocking activation of adaptive cancer pathways, presents important approaches to improving treatment outcomes in cancer