Theoretical study of the Coriolis effect in LiNa, LiK, and LiRb molecules.

The non-adiabatic electronic matrix elements, LΠΣ(R), that arise from the spin-conserving electron-rotational interactions between all mΣ+ and mΠ states, where multiplicity m = 1, 3, converging to the lowest three dissociation limits of Li-containing alkali diatomics, LiM (M = Na, K, Rb), were calculated ab initio up to large internuclear distances, R. The required electronic wavefunctions were obtained within the framework of the multi-reference configuration interaction treatment of the two-valence-electron problem constructed using small-core scalar-relativistic effective core potentials and l-independent core-polarization potentials. A least squares analysis of the ab initio functions at large internuclear distances in conjunction with long-range perturbation theory (LRPT) revealed three different asymptotic behaviors of the LΠΣ(R → +∞)-functions: const. + ß[n]/Rn, characterized by n = -1, 3 and 6. The asymptotic coefficients ß[n], extracted from the point-wise ab initio data, were found to be in agreement with their LRPT counterparts, which were evaluated analytically using the relevant atomic parameters. The mass dependence of the LΠΣ matrix elements was investigated analytically and numerically. To confirm the reliability of the LΠΣ(R)-functions and interatomic potentials at small and intermediate distances, the empirical q-factors available for the D1Π-states of all LiM molecules studied were compared with their theoretical counterparts derived from the present ab initio data.

A first principles study of the spin-orbit coupling effect in LiM (M = Na, K, Rb, Cs) molecules.

The spin-orbit (SO) interactions in low-lying electronic states of the LiM (M = Na, K, Rb, Cs) molecular series are studied through ab initio calculations of potential energy curves and SO coupling matrix elements as functions of the interatomic distance, R. Two different approaches are employed: (a) the Fock-space relativistic coupled-cluster calculations (FS-RCC) which directly yield full relativistic energies, Urel(R); the SO coupling functions, ξso(R), are extracted a posteriori through projecting scalar-relativistic wave functions onto the subspaces spanned by their full-relativistic counterparts; (b) the evaluation of the scalar-relativistic electronic energies, Usr(R), and relevant ξso(R) functions using the configuration interaction method with core-valence correlation accounted for using core polarization potentials (CI-CPP). The SO-free potentials and SO coupling functions obtained within the framework of both approaches are in good agreement with each other and their prior theoretical and empirical counterparts.

Production of Recombinant Polypeptides Binding α2-Macroglobulin and Analysis of Their Ability to Bind Human Serum α2-Macroglobulin.

Many streptococcal strains bind to two main human blood plasma proteins: IgG and human serum albumin (HSA). Protein G expressed in group C and G streptococci has specific binding regions for these proteins. Protein G in group G streptococcal strains also contains a region binding another human plasma protein, α2-macroglobulin (α2-М), upstream to the HSA-binding domain. Two recombinant polypeptides GM and GM1 capable of binding to α2-М were obtained using the G4223 strain of a group G Streptococcus, protein G molecule of which interacts with three human blood serum proteins (IgG, HSA, and α2-М). However, polypeptide GM containing three IgG-binding and three HSA-bindings domains and the region binding α2-М has higher molecular mass and higher affinity to α2-М than polypeptide GM1 that includes only the α2-М binding region.

Long-range behavior of the transition dipole moments of heteronuclear dimers XY (X, Y = Li, Na, K, Rb) based on ab initio calculations.

The ab initio electronic transition dipole moments (ETDMs) of heteronuclear dimers XY (X, Y = Li, Na, K, Rb) were calculated between the ground and excited states converging to the lowest three dissociation limits. The spin-allowed ETDMs were evaluated in a wide range of interatomic distances, R, by means of the quasi-relativistic electronic wave functions obtained by the multi-reference configuration interaction method. The inner-shell electrons (2 electrons for Li and Na atoms, and 10 and 28 for K and Rb, respectively) were described using the non-empirical shape-consistent effective core potentials. The l-independent core polarization potentials of each atom were used to take core-polarization and core-valence correlation effects into account. The long-range behavior of both singlet-singlet X1Σ+-(2,3)1Σ+;(1,2)1Π and triplet-triplet a3Σ+-(2,3)3Σ+;(1,2)3Π transition moments is perfectly fitted at large R-distance by the asymptotic formula of X. Chu and A. Dalgarno, Phys. Rev. A: At., Mol., Opt. Phys., 2002, 66, 024701: , where the coefficient ß is equal to 2 and -1 for the Σ-Σ and Σ-Π transitions, respectively. The n2S-n2P transition moments, dA, and dynamic polarizabilites, αB, of the alkali atoms in the n2S state extracted from the present molecular calculations coincide with their empirical and ab initio counterparts to within a few percent.

Expression of New Recombinant IgG-Binding Polypeptides and Analysis of Their Capacity to Bind Human IgG.

Protein G is present in group G streptococcus strain (G4223); the IgG-binding part of this protein contains three IgG-binding domains and binds human IgG with very high activity. We obtained two recombinant polypeptides G4223 and G14223 with high IgG-binding activity. Polypeptide G14223 consisting of three IgG-binding domains and W region has higher molecular weight and is characterized by higher affinity for IgG than polypeptide G4223 consisting of only three IgG-binding domains. It was shown that polypeptide affinity depends on its structure and size.

Production of Recombinant Polypeptides Containing One GA-Module and Analysis of Their Ability to Bind to Human Albumin.

Surface proteins of many bacterial species interact with human serum albumin (HSA) via a special region of amino acid sequence termed GA module. For instance, surface peptostreptococcal albumin-binding protein of anaerobic bacteria Peptostreptococcus magnus contains one HSA-binding GA-module. Protein G from group G and C Streptococcus strains isolated from humans has HSA-binding region consisting of three GA-modules. HSA-binding protein containing two GA-modules was found in strains of group G Streptococcus of animal origin. We obtained two recombinant polypeptides GA1 and GA2 congaing one GA-module each. Recombinant polypeptide with two GA-modules binds HSA with a much higher affinity than polypeptides GA1 and GA2 containing one GA-module. Polypeptide with the second GAmodule more effectively binds HSA than polypeptides with the GA-module.

[The test-system for detection of microalbuminuria using the new recombinant albumin-bounded poly-peptide].

The diabetes mellitus and arterial hypertension are among the most significant pathologies conditioning disorder of excretion of protein with urine. These very diseases are mostly dangerous for kidneys. Therefore, important significance has the search of early manifestations of damage of kidneys in patients with these diseases. The microalbuminuria is one of early manifestations of affection of kidneys in patients with diabetes mellitus and arterial hypertension. Only this early (pre-clinical) stage of affection of kidneys is the only reversible one in case of prescription of medicinal therapy. Nowadays, factually all applied diagnostic test-systems for detection ofmicroalbuminuria are based on immunological half-quantitative and quantitative detection of concentration of human serum albumin in urine. In this study was applied new recombinant human serum poly-peptide A3 from strain of streptococcus group G isolated from cow milk. The human serum albumin-binding capacity of poly-peptide A3 was analyzed in comparison with poly-peptide A2. Previously, recombinant human serum albumin-binding poly-peptide A2 was primarily applied in test-system for detection of microalbuminuria instead of commonly used antibodies. The analysis of 'human serum albumin-binding capacity of recombinant human serum poly-peptide A3 and A2 demonstrated that both of them can interact with human serum albumin in solution and adsorbed condition. This characteristic permitted applying poly-peptide A3 in immobilized form in qualitative test-system for detecting microalbuminuria. The actual study also propose specific and sensitive technique of screening and monitoring of patients with diabetes mellitus and arterial hypertension. The mentioned technique used tagged human serum albumin-binding polypeptide A3 combined with microchip technology. The comparison of test-systems using recombinant poly-peptides A3 and A2 established that application of poly-peptide A3 in test-system permits to detect more precisely concentration of human serum albumin in urine samples. The test-system of this kind was successfully implemented for both detection and qualitative identification of microalbuminuria in patients with diabetes mellitus and arterial hypertension.

The Relationship between Albumin-Binding Capacity of Recombinant Polypeptide and Changes in the Structure of Albumin-Binding Domain.

Many bacteria express surface proteins interacting with human serum albumin (HSA). One of these proteins, PAB from anaerobic bacteria, contains an albumin-binding domain consisting of 45 amino acid residues known as GA domain. GA domains are also found in G proteins isolated from human streptococcal strains (groups C and G) and of albumin-binding protein isolated from group G streptococcal strains of animal origin. The GA domain is a left-handed three-helix bundle structure in which amino acid residues of the second and third helixes are involved in albumin binding. We studied the relationship between HSA-binding activity of the recombinant polypeptide isolated from group G streptococcus of animal origin and structure of the GA domain is studied. Structural changes in GA domain significantly attenuated HAS-binding capacity of the recombinant polypeptide. Hence, affinity HSA-binding polypeptide depends on stability of GA domain structure.

[A New Approach to the Depletion of Albumin and Immunoglobulin G from Human Serum].

The use of proteomic analysis to find potential diagnostic biomarkers is limited by the presence of serum albumin (HSA) and immunoglobulin (IgG) at high concentrations in patients' blood; these substances impede the detection of serum proteins with similar molecular weights. Recombinant HSA- and IgG-binding polypeptides are used as ligands in creating sorbents for complete removal of the proteins by affinity chromatography. The binding specificity of the sorbents for HAS and IgG is higher than that of the conventionally used antibodies. A composite sorbent enabling the depletion of HSA and IgG from serum by single-step affinity chromatography is obtained. The. developed sorbents were used to prepare serum for proteomic analysis.