Respiratory syncytial virus (RSV) is the major respiratory tract pathogen in infancy. Host-related differences in susceptibility to severe RSV infection suggest that genetic factors may play a role. In this study, a candidate-gene approach was used to study whether the surfactant protein D (SP-D) gene polymorphism associates with severe RSV infection. DNA samples from 84 infants hospitalized for the treatment of RSV bronchiolitis and 93 healthy controls were analyzed. The controls were matched with the cases on the basis of sex, hospital district, date of birth (Ϯ2 wk) and gestational age at birth (Ϯ2 wk). Three biallelic SP-D gene polymorphisms were genotyped. Significant differences were observed in the SP-D allele frequencies for amino acid 11 between the RSV infants and their matched controls. The frequency of the allele coding for Met 11 (p ϭ 0.033) was increased in the severe RSV group. The frequency of the homozygous genotype Met/Met for amino acid 11 was increased in the RSV group relative to the controls, whereas the heterozygous genotype tended to be less frequent among the RSV cases than in the matched controls. Conditional logistic regression analysis was used to study whether the confounders, i.e. smoking and number of children in the family, influence the association between the homozygous SP-D genotype for methionine 11 and the risk of RSV bronchiolitis. The results further confirmed this association (p ϭ 0.028). To our knowledge, the present report provides the first evidence of a specific gene associated with susceptibility to severe RSV infection. Respiratory syncytial virus (RSV) is a major respiratory tract pathogen in early childhood. In young infants, seasonal epidemics of RSV cause 50% of the severe instances of bronchiolitis that require hospital treatment and may be fatal. Environmental factors, gender, and socioeconomic status all play a role in RSV infections, but the host-related differences in susceptibility suggest that genetic factors contribute to the risk of contracting this disease (1).Pulmonary surfactant, a complex mixture of phospholipids and surfactant proteins, lines the alveolar surface of the lung and is essential for normal respiratory function. Surfactant protein D (SP-D) was first described in association with alveolar surfactant. However, this protein does not bind to the surfactant complex and has been found elsewhere in the airways. SP-D is a collagenous C-type lectin mainly assembled as dodecamers consisting of four homotrimeric subunits. SP-D has several immunomodulatory functions, including agglutination of some viruses that cause airway disease (2).Concentrations of the surfactant components are decreased in viral bronchiolitis (3, 4). Studies with a mouse model have shown dysfunction of the surfactant complex in RSV induced pulmonary infections (5). Hickling et al. (6) showed that intranasal administration of recombinant SP-D domain to RSV-infected mice reduced the levels of lung virus by 80%, suggesting that SP-D plays a major role in clearing RSV from the lu...

* The controls were matched to the cases for sex, hospital district, date of birth (Ϯ2 weeks) and gestational age at birth (Ϯ2 weeks). More than one control was allowed for each RSV patient. † At least one parent smokes.

No abstract

No abstract

Surfactant protein C (SP-C) is a small hydrophobic protein component of alveolar surfactant, a lipidprotein complex lining the alveolar surface of the lung. Surfactant deficiency is the main cause of respiratory distress syndrome (RDS) in premature infants. RDS is a major risk factor of a chronic lung disease called bronchopulmonary dysplasia (BPD). The dominant mutations of the SP-C gene have recently been associated with interstitial lung diseases. However, the common genetic variation in the surfactant protein C gene has not been studied in detail. In the present study, the exonic variation of the SP-C gene in the Finnish population (n ¼ 472) was defined, and the association of the allelic variants with the susceptibility to RDS and BPD was examined. Conformation-sensitive gel electrophoresis (CSGE) was used to determine the extent of exonic variation in the SP-C gene. Methods of genotyping were generated for three biallelic polymorphisms of the SP-C gene's exons 1, 4 and 5, which encode proSP-C. The frequencies of these polymorphisms were evaluated in a study population consisting of 158 DNA samples from fullterm infants. In addition, the linkage disequilibrium between the SP-C alleles was evaluated by haplotype analysis of parent -infant triplets. The role of SP-C gene variation in RDS and in BPD was evaluated in a high-risk population of 245 premature infants. According to the present results, the SP-C polymorphisms were associated with RDS and with very premature birth. The strength of allelic associations differed according to the gender of the premature infants.

Background:The integrin ␣I domain undergoes a conformational change during activation. Results: The crystal structure of an activated ␣I domain is different from the reported open and closed states. Conclusion: Our structure mimics the state where the Arg 287 -Glu 317 ion pair is just broken during the activation process. Significance: The activation mechanism of the collagen receptor integrins differs from the other integrins.

Yeast exopolyphosphatase (scPPX) processively splits off the terminal phosphate group from linear polyphosphates longer than pyrophosphate. scPPX belongs to the DHH phosphoesterase superfamily and is evolutionarily close to the well characterized family II pyrophosphatase (PPase -bound enzyme. These results provide an initial step toward understanding the dynamics of scPPX catalysis and reveal significant functional differences between structurally similar scPPX and family II PPase. Linear inorganic polyphosphates (polyP)3 comprising chains of tens to hundreds of phosphate units are conserved in all cells, and thus are possible agents of evolution from prebiotic times (1, 2). In eukaryotes, they account for up to 20% of dry cell weight (1, 2). Recent evidence indicates that rather than simply being a store of phosphate and energy, polyP are required for bacterial responses to a variety of stress and stringency conditions, as well as for virulence of some pathogens (3-5). PolyP are additionally involved in blood clotting (6) and proliferation of mammary cancer cells (7).PolyP are synthesized by polyphosphate kinase, and hydrolyzed by exo-and endopolyphosphatases. Exopolyphosphatase (PPX) processively releases the terminal phosphate groups from polyP formed by Ն3 phosphate residues. Based on the primary structure, PPXs are classified into two types, whose prototypes are PPXs from yeast (Saccharomyces cerevisiae) cytosol and Escherichia coli. Yeast-type PPX, reported in fungi and protozoa, belongs to the superfamily of DHH phosphoesterases (named after the conserved Asp-His-His motif) (8), whereas E. coli-type PPX is present in Eubacteria and Archaea and belongs to a sugar kinase/actin/hsp-70 superfamily (9). Genes of both yeast-type PPXs (from S. cerevisiae and Leishmania major) and E. coli type PPXs (from E. coli, Aquifex aeolicus and Sulfolobus solfataricus) have been expressed in E. coli (10 -14), and the structures of S. cerevisiae (15), E. coli (16), 4 and A. aeolicus (E. coli type) (18) PPXs have been determined. The overall folds of the two PPX families are dissimilar. Specifically, the subunits comprise two domains in yeast-type PPX and four domains in E. coli-type PPX. However, in both families, the active site is located between the domains connected by a flexible linker. Interestingly, yeast and A. aeolicus PPXs are monomeric proteins (15, 18 -20), whereas E. coli PPX is dimeric (10, 16). 4 Interestingly, the yeast cell contains up to five different exopolyphosphatases in different compartments (22).The overall structure of yeast cytosolic PPX (scPPX) bears a striking similarity to that of the well characterized family II pyrophosphatase (PPase) (23, 24), a DHH phosphoesterase that catalyzes a similar reaction with pyrophosphate, the shortest polyphosphate. Despite only 12-17% sequence identity, 11 of the total 14 polar residues in the active site of family II PPase are conserved in all yeast-type PPXs, and two more are conserved in most of the enzymes (Fig. 1A), implying an evolutionary relationship. M...

Integrin alpha2beta1 is a potential target molecule in drug development. We have established "design" criteria for molecules that bind to the "closed" conformation of alpha2I domain via Mg(2+) in MIDAS (metal ion dependent adhesion site) while simultaneously forming interactions with neighboring amino acid residues. Specific tetracyclic Streptomyces products belonging to the group of aromatic polyketides fulfill our criteria and inhibit alpha2beta1 integrin. All previously described inhibitors of alphaI domain integrins act in an allosteric manner.