p53 abnormalities are not a significant prognostic factor in primary, resected NSCLC when all histologic subtypes are combined, but may be a useful prognosticator for adenocarcinomas. Additional studies are warranted for further evaluation, specifically of adenocarcinomas.
Combined deficiency of coagulation factors V and VIII (F5F8D), an autosomal recessive disorder characterized by coordinate reduction in the plasma levels of factor V (FV) and factor VIII (FVIII), is genetically linked to mutations in the transmembrane lectin ERGIC-53 and the soluble calcium-binding protein MCFD2. Growing evidence indicates that these two proteins form a complex recycling between the endoplasmic reticulum (ER) and the ER-Golgi intermediate compartment and thereby function as a cargo receptor in the early secretory pathway of FV and FVIII. For better understanding of the mechanisms underlying the functional coordination of ERGIC-53 and MCFD2, we herein characterize their interaction by x-ray crystallographic analysis in conjunction with NMR and ultracentrifugation analyses. Inspection of the combined data reveals that ERGIC-53-CRD binds MCFD2 through its molecular surface remote from the sugar-binding site, giving rise to a 1∶1 complex in solution. The interaction is independent of sugarbinding of ERGIC-53 and involves most of the missense mutation sites of MCFD2 so far reported in F5F8D. Comparison with the previously reported uncomplexed structure of each protein indicates that MCFD2 but not ERGIC-53-CRD undergoes significant conformational alterations upon complex formation. Our findings provide a structural basis for the cooperative interplay between ERGIC-53 and MCFD2 in capturing FV and FVIII.MCFD2 | ERGIC-53 | calcium-binding protein | cargo receptor | intracellular lectin C ombined deficiency of coagulation factors V and VIII (F5F8D) is an autosomal recessive disorder characterized by coordinate reduction in the plasma levels of factor V (FV) and factor VIII (FVIII) (1, 2) Extensive genetic analysis of F5F8D patients identified two genes that are associated with this disorder. Genetic mutations in LMAN1 account for approximately 70% of F5F8D families, whereas the remaining 30% families possess mutation in MCFD2 (3, 4). LMAN1 encodes the transmembrane lectin ERGIC-53 (ER-Golgi intermediate compound protein of 53 kDa) (5), which possesses a luminal carbohydrate recognition domain (CRD) with specificity for highmannose-type oligosaccharides (6, 7) and forms dimers or hexamers stabilized by disulfide bonds formed in its stalk domain (5, 8). By contrast, the product of MCFD2 is a soluble luminal protein with two EF-hand Ca 2þ -binding motifs (9). It has been shown that MCFD2 interacts with the CRD of ERGIC-53 in a Ca 2þ -dependent manner (9-11). Accumulating evidence indicates that this complex recycles between the endoplasmic reticulum (ER) and the ER-Golgi intermediate compartment (ERGIC) and thereby functions as a cargo receptor in the early secretory pathway of FV and FVIII (12).To gain a better understanding of the molecular mechanisms underlying the sorting and trafficking of these coagulation factors, it is essential to shed light on the structural basis of the cooperative interplay between ERGIC-53 and MCFD2. The crystallographic data of the CRD of rat ERGIC-53 have revealed that it com...
We isolated and determined the complete genome sequence of a KPC-2-producing K. pneumoniae strain from a sampling site in Tokyo Bay, Japan, near a wastewater treatment plant (WWTP). In Japan, the KPC type has been very rarely detected, while IMP is the most predominant type of carbapenemase in clinical carbapenemase-producing Enterobacteriaceae (CPE) isolates. Although laboratory testing thus far suggested that Japan may be virtually free of KPC-producing Enterobacteriaceae, we have detected it from effluent from a WWTP. Antimicrobial resistance (AMR) monitoring of WWTP effluent may contribute to the early detection of future AMR bacterial dissemination in clinical settings and communities; indeed, it will help illuminate the whole picture in which environmental contamination through WWTP effluent plays a part.
DNA primases are essential components of the DNA replication apparatus in every organism. Reported here are the biochemical characteristics of a thermostable DNA primase from the thermophilic archaeon Pyrococcus horikoshii, which formed the oligomeric unit L(1)S(1) and synthesized long DNA primers 10 times more effectively than RNA primers. The N-terminal (25KL) and C-terminal halves (20KL) of the large subunit (L) play distinct roles in regulating de novo DNA synthesis of the small catalytic subunit (S). The 25KL domain has a dual function. One function is to depress the large affinity of the intrasubunit domain 20KL for the template DNA until complex (L(1)S(1) unit) formation. The other function is to tether the L subunit tightly to the S subunit, probably to promote effective interaction between the intrasubunit domain 20KL and the active center of the S subunit. The 20KL domain is a central factor to enhance the de novo DNA synthesis activity of the catalytic S subunit since the total affinity of the L(1)S(1) unit is mainly derived from the affinity of 20KL, which is elevated more than 10 times by the heterodimer formation, presumably due to the cancellation of the inhibitory activity of 25KL through tight binding to the S subunit.
In NSCLC, the incidence of p53 autoantibodies is associated with histologic type, stage, and p53 overexpression--but not with patient survival. Our data do not support the clinical utility of p53 autoantibodies as diagnostic or prognostic markers in patients with NSCLC.
BackgroundPost-dural puncture headache (PDPH) due to excessive cerebrospinal fluid (CSF) leakage is a well-known complication of lumbar puncture. Although various factors, especially the type of spinal needle, have been demonstrated to be associated with PDPH, the clinical implications of CSF leakage detected on magnetic resonance myelography (MRM) images remain unclear. The objective of this case–control study was to evaluate the association between radiologically visualized CSF leakage and PDPH.MethodsClinical data including patients’ age and gender, types of spinal needle, duration of bed rest, interval between lumbar puncture procedures and MRM studies, and incidence of PDPH were compared between patients who were radiologically-positive and -negative for CSF leakage.ResultsOf the 22 patients with definite CSF leakage on MRM images, most were asymptomatic (86%, 19/22). The remaining three patients, who were suffering from PDPH, only complained of headaches and were treated conservatively. In a review of patients’ clinical data, there were no significant differences in any parameter including the incidence of PDPH between the 22 patients who were radiologically-positive for CSF leakage and the 31 radiologically-negative patients.ConclusionThe significance of radiologically visualized CSF leakage should not be overestimated, as most such incidents are not associated with PDPH and do not require any treatment.
The beta-glycosidase of the hyperthermophilic Archaeon Pyrococcus horikoshii is a membrane-bound enzyme with the preferred substrate of alkyl-beta-glycosides. In this study, the unusual structural features that confer the extreme thermostability and substrate preferences of this enzyme were investigated by X-ray crystallography and docking simulation. The enzyme was crystallized in the presence of a neutral surfactant, and the crystal structure was solved by the molecular replacement method and refined at 2.5 A. The main-chain fold of the enzyme belongs to the (betaalpha)8 barrel structure common to the Family 1 glycosyl hydrolases. The active site is located at the center of the C-termini of the barrel beta-strands. The deep pocket of the active site accepts one sugar unit, and a hydrophobic channel extending radially from there binds the nonsugar moiety of the substrate. The docking simulation for oligosaccharides and alkylglucosides indicated that alkylglucosides with a long aliphatic chain are easily accommodated in the hydrophobic channel. This sparingly soluble enzyme has a cluster of hydrophobic residues on its surface, situated at the distal end of the active site channel and surrounded by a large patch of positively charged residues. We propose that this hydrophobic region can be inserted into the membrane while the surrounding positively charged residues make favorable contacts with phosphate groups on the inner surface of the membrane. The enzyme could thus adhere to the membrane in the proximity of its glycolipid substrate.
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