Folding and Binding Properties of Human Complement Receptor Type 1 Extracellular Domain

Complement receptor type 1 (CR1 or CD35) is a peripheral glycosylated membrane protein that regulates the complement activation in the control of immune responses. The author would like to overview the folding and binding properties of the soluble form of CR1, so-called as sCR1, introducing our development of the high-yield overexpression and purification methods as well as the investigation to its molecular structure. Although sCR1 prepared through our method showed the highest binding affinity against C3b, it is quite difficult to be crystallized for X-ray structure analysis. In spite of many attempts, only microcrystals have been obtained so far. Considering the usefulness to understand factors within the difficulty, the primary sequence of sCR1 has been reexamined from the viewpoints both of secondary structure predictions and recent findings of intrinsically disordered proteins (IDPs) or natively unfolded proteins (NUPs). As an example, the theoretically predicted structure of a short consensus repeat (SCR) of a binding domain, SCR-15–17 in sCR1 is compared with the reported solution structure by NMR. The discussion is extended to protein structure studies with proteins containing ID regions, which are unfolded state without taking uniformly decided structures

Structure of RadB recombinase from a hyperthermophilic archaeon, Thermococcus kodakaraensis KOD1: an implication for the formation of a near-7-fold helical assembly

The X-ray crystal structure of RadB from Thermococcus kodakaraensis KOD1, an archaeal homologue of the RecA/Rad51 family proteins, have been determined in two crystal forms. The structure represents the core ATPase domain of the RecA/Rad51 proteins. Two independent molecules in the type 1 crystal were roughly related by 7-fold screw symmetry whereas non-crystallographic 2-fold symmetry was observed in the type 2 crystal. The dimer structure in the type 1 crystal is extended to construct a helical assembly, which resembles the filamentous structures reported for other RecA/Rad51 proteins. The molecular interface in the type 1 dimer is formed by facing a basic surface patch of one monomer to an acidic one of the other. The empty ATP binding pocket is located at the interface and barely concealed from the outside similarly to that in the active form of the RecA filament. The model assembly has a positively charged belt on one surface bordering the helical groove suitable for facile binding of DNA. Electron microscopy has revealed that, in the absence of ATP and DNA, RadB forms a filament with a similar diameter to that of the hypothetical assembly, although its helical properties were not confirmed

The first case of recurrent ultra late onset group B streptococcal sepsis in a 3-year-old child

AbstractGroup B streptococcus (GBS) is a commonly recognized cause of sepsis and meningitis in neonatal and young infants. Invasive GBS infection is classified into early onset GBS disease (EOD, day 0–6), late onset GBS disease (LOD, day 7–89) and ultra late onset GBS disease (ULOD, after 3 months of age). ULOD is uncommon and recurrence is especially rare. We present the first recurrent case of ULOD GBS sepsis in 3-year-old girl with a past medical history of hydrops fetalis and thoracic congenital lymphatic dysplasia. The first episode presented as sepsis at 2 years 8 months of age. The second episode occurred as sepsis with encephalopathy at 3 years 1 months of age. During each episode, the patient was treated using intravenous antimicrobials and her condition improved. Serotype examination was not performed in the first episode, but GBS type V was serotyped in the second episode. ULOD over 1year of age is quite rare and may recur

Enhancement of astaxanthin production in Xanthophyllomyces dendrorhous by efficient method for the complete deletion of genes

Additional file 1. DNA seuence of primers used in this study

Variation of Pressure-Induced Valence Transition with Approximation Degree in Yb-Based Quasicrystalline Approximants

We have synthesized new Tsai-type Yb-based intermediate-valence approximant crystals (ACs) with different degree of approximation to quasicrystal, Zn--Au--Yb 1/1 and 2/1 AC, and studied the external pressure effect on their Yb mean-valence $\nu$. Whereas 1/1 AC distinctly exhibits a first-order-like jump in $\nu$ at a transition pressure $P_{\rm v}$, 2/1 AC only shows an indistinct anomaly at $P_{\rm v}$. We have also studied the pressure dependence of the $\nu$ of Au--Al--Yb 1/1 AC, which is a prototypal AC exhibiting pressure-induced quantum criticality. It shows a continuous valence anomaly at a critical pressure $P_{\rm c}$ where the magnetic susceptibility diverges toward zero temperature, in contrast to the valence jump in the Zn--Au--Yb 1/1 AC. These results are discussed based on a theoretical model of quantum critical valence fluctuation

The lysophosphatidic acid receptor LPA(4) regulates hematopoiesis-supporting activity of bone marrow stromal cells

Lysophosphatidic acid (LPA) is a pleiotropic lipid mediator that acts through G protein-coupled receptors (LPA(1-6)). Although several biological roles of LPA(4) are becoming apparent, its role in hematopoiesis has remained unknown. Here, we show a novel regulatory role for LPA(4) in hematopoiesis. Lpar4 mRNA was predominantly expressed in mouse bone marrow (BM) PDGFR alpha(+) stromal cells, known as the components of the hematopoietic stem/progenitor cell (HSPC) niche. Compared with wild-type mice, LPA(4)-deficient mice had reduced HSPC numbers in the BM and spleen and were hypersusceptible to myelosuppression, most likely due to impairments in HSPC recovery and stem cell factor production in the BM. Analysis of reciprocal BM chimeras (LPA(4)-deficient BM into wild-type recipients and vice versa) indicated that stromal cells likely account for these phenotypes. Consistently, LPA(4)-deficient BM stromal cells showed downregulated mRNA expression of stem cell factor and tenascin-c in vitro. Taken together, these results suggest a critical and novel role for the LPA/LPA(4) axis in regulating BM stromal cells

Diagnostic utility of C-reactive Protein combined with brain natriuretic peptide in acute pulmonary edema: a cross sectional study

Introduction Discriminating acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) from cardiogenic pulmonary edema (CPE) using the plasma level of brain natriuretic peptide (BNP) alone remains controversial. The aim of this study was to determine the diagnostic utility of combination measurements of BNP and C-reactive protein (CRP) in critically ill patients with pulmonary edema