Characterization of inhibitory and stimulatory forms of the murine natural killer cell receptor 2B4

The receptor 2B4 belongs to the Ig superfamily and is found on the surface of all murine natural killer (NK) cells as well as T cells displaying non-MHC-restricted cytotoxicity. Previous studies have suggested that 2B4 is an activating molecule because cross-linking of this receptor results in increased cytotoxicity and γ-interferon secretion as well as granule exocytosis. However, it was recently shown that the gene for 2B4 encodes two different products that arise by alternative splicing. These gene products differ solely in their cytoplasmic domains. One form has a cytoplasmic tail of 150 amino acids (2B4L) and the other has a tail of 93 amino acids (2B4S). To determine the function of each receptor, cDNAs for 2B4S and 2B4L were transfected into the rat NK cell line RNK-16. Interestingly, the two forms of 2B4 had opposing functions. 2B4S was able to mediate redirected lysis of P815 tumor targets, suggesting that this form represents an activating receptor. However, 2B4L expression led to an inhibition of redirected lysis of P815 targets when the mAb 3.2.3 (specific for rat NKRP1) was used. In addition, 2B4L constitutively inhibits lysis of YAC-1 tumor targets. 2B4L is a tyrosine phosphoprotein, and removal of domains containing these residues abrogates its inhibitory function. Like other inhibitory receptors, 2B4L associates with the tyrosine phosphatase SHP-2. Thus, 2B4L is an inhibitory receptor belonging to the Ig superfamily.

Peroxo-iron and oxenoid-iron species as alternative oxygenating agents in cytochrome P450-catalyzed reactions: switching by threonine-302 to alanine mutagenesis of cytochrome P450 2B4.

Among biological catalysts, cytochrome P450 is unmatched in its multiplicity of isoforms, inducers, substrates, and types of chemical reactions catalyzed. In the present study, evidence is given that this versatility extends to the nature of the active oxidant. Although mechanistic evidence from several laboratories points to a hypervalent iron-oxenoid species in P450-catalyzed oxygenation reactions, Akhtar and colleagues [Akhtar, M., Calder, M. R., Corina, D. L. & Wright, J. N. (1982) Biochem. J. 201, 569-580] proposed that in steroid deformylation effected by P450 aromatase an iron-peroxo species is involved. We have shown more recently that purified liver microsomal P450 cytochromes, including phenobarbital-induced P450 2B4, catalyze the analogous deformylation of a series of xenobiotic aldehydes with olefin formation. The investigation presented here on the effect of site-directed mutagenesis of threonine-302 to alanine on the activities of recombinant P450 2B4 with N-terminal amino acids 2-27 deleted [2B4 (delta2-27)] makes use of evidence from other laboratories that the corresponding mutation in bacterial P450s interferes with the activation of dioxygen to the oxenoid species by blocking proton delivery to the active site. The rates of NADPH oxidation, hydrogen peroxide production, and product formation from four substrates, including formaldehyde from benzphetamine N-demethylation, acetophenone from 1-phenylethanol oxidation, cyclohexanol from cyclohexane hydroxylation, and cyclohexene from cyclohexane carboxaldehyde deformylation, were determined with P450s 2B4, 2B4 (delta2-27), and 2B4 (delta2-27) T302A. Replacement of the threonine residue in the truncated cytochrome gave a 1.6- to 2.5-fold increase in peroxide formation in the presence of a substrate, but resulted in decreased product formation from benzphetamine (9-fold), cyclohexane (4-fold), and 1-phenylethanol (2-fold). In sharp contrast, the deformylation of cyclohexane carboxaldehyde by the T302A mutant was increased about 10-fold. On the basis of these findings and our previous evidence that aldehyde deformylation is supported by added H202, but not by artificial oxidants, we conclude that the iron-peroxy species is the direct oxygen donor. It remains to be established which of the many other oxidative reactions involving P450 utilize this species and the extent to which peroxo-iron and oxenoid-iron function as alternative oxygenating agents with the numerous isoforms of this versatile catalyst.

FMDV 2B biroporina aktibitatearen liposoma-saioak eta erabilpena antibiralen garapenean

FMDV 2B biroporinak duen egitura eta funtzio aztertzeko helburuarekin, peptidoetan oinarritutako analisiak egin dira. Modu honetan, 2B proteina ezestrukturalak bi transmintz domeinu agertu ditu, II motako biroporina dela bermatuz. FMDV 2B biroporinaren aminoazido sekuentziak pikornabirusen 2B aminoazido sekuentziekin homologia erakusten du, 2B4 peptidoari dagokion sekuentzia gehigarria kontuan hartu gabe. Sekuentzia gehigarri hau bigarren domeinu litiko bat da, birus familia honetan deigarria dena. Jakinik birusek haien bizi zikloa aurrera eramateko behar-beharrezkoa den material genetikoa baino ez dutela, bi domeinu litiko izateak ebolutiboki zein funtzionalki garrantzia handia duela onar daiteke.

Clinical and biochemical description of a novel CYP21A2 gene mutation 962_963insA using a new 3D model for the P450c21 protein

OBJECTIVE: A severely virilized 46, XX newborn girl was referred to our center for evaluation and treatment of congenital adrenal hyperplasia (CAH) because of highly elevated 17alpha-hydroxyprogesterone levels at newborn screening; biochemical tests confirmed the diagnosis of salt-wasting CAH. Genetic analysis revealed that the girl was compound heterozygote for a previously reported Q318X mutation in exon 8 and a novel insertion of an adenine between nucleotides 962 and 963 in exon 4 of the CYP21A2 gene. This 962_963insA mutation created a frameshift leading to a stop codon at amino acid 161 of the P450c21 protein. AIM AND METHODS: To better understand structure-function relationships of mutant P450c21 proteins, we performed multiple sequence alignments of P450c21 with three mammalian P450s (P450 2C8, 2C9 and 2B4) with known structures as well as with human P450c17. Comparative molecular modeling of human P450c21 was then performed by MODELLER using the X-ray crystal structure of rabbit P450 2B4 as a template. RESULTS: The new three dimensional model of human P450c21 and the sequence alignment were found to be helpful in predicting the role of various amino acids in P450c21, especially those involved in heme binding and interaction with P450 oxidoreductase, the obligate electron donor. CONCLUSION: Our model will help in analyzing the genotype-phenotype relationship of P450c21 mutations which have not been tested for their functional activity in an in vitro assay.

Pechas de Navarra vindicadas : Consulta en que se resuelve, y demuestra, que las pechas de este Reyno, que se hallaren fixas á las heredades, ó cargadas en ellas, no son, ni deben ser impedimento al hidalgo, su posseedor, para el goze de los fueros, esenciones, y privilegios de hidalgo / por el P. Fr. Joseph de San Francisco Xavier.

Sign.: []4, [calderón-2calderón]4, A-Z4, 2A-2B4, 2C8, 2D4, 2E2

Constituciones synodales del obispado de Calahorra y la Calzada / hechas y ordenadas por... Pedro Gonçalez de Castillo... en el synodo diocesano que se celebró en... Logroño en el año de mil y seyscientos y veynte.

Digitalización Vitoria-Gasteiz Fundación Sancho el Sabio 2010

Clarissimi ... Pauli Soncinatis ... Ordinis Predicatorum, Diuinum Epitoma Questionum in quatuor libros Sententiarum a ... Joanne Capreolo Tholosano disputatarum / his additisque idem morte preuentus perficere nequiuit, per fratem Isidorum de Isolanis ...

Capitulares grab. xil.

Clarissimi ... Pauli Soncinatis ... Ordinis Predicatorum, Diuinum Epitoma Questionum in quatuor libros Sententiarum a ... Joanne Capreolo Tholosano disputatarum / his additisque idem morte preuentus perficere nequiuit, per fratem Isidorum de Isolanis ...

Capitulares grab. xil.

Diui Aurelij Augustini hipponensis ep[iscop]i ... aureorum Sermonu[m] nuper accuratissime Lugduni speciofissimis characteribus impressorum Prima-[secunda] pars ...

Pie de imp. tomado de colofón en B10v

Diui Aurelij Augustini hipponensis ep[iscop]i ... aureorum Sermonu[m] nuper accuratissime Lugduni speciofissimis characteribus impressorum Prima-[secunda] pars ...

Pie de imp. tomado de colofón en B10v

In Euangelium Lucae paraphrasis / Erasmi Roterodami, per autorem recognita.

Sign.: 2A8, 2B4, a-z8, A-K8

In Euangelium Lucae paraphrasis / Erasmi Roterodami, per autorem recognita.

Sign.: 2A8, 2B4, a-z8, A-K8

Macrobii Aurelii Theodosii viri consularis in Somnium Scipionis libri duo, et septem eiusdem Saturnaliorum : nunc denuo recogniti, & multis in locis aucti.

Sign.: 2A6, 2B4, a-n8, o-p6, q-s8

Morales / de Plutarco ; traduzidos de lengua griega en castellana ...

Según Martin Abad hay diversos estados de esta ed.

Descrittione del Regno di Napoli nella quale s'ha piena contezza, cosi' del sito d'esso, de'nomi delle prouintie antiche ... come de'monti, de'mari ... Et vi si fa mentione de i re, con la loro vita, & effigie, che l'han dominato ... le loro arme ... e con un preambolo de i re di Gierusalem, oue si dichiara perche i re di Napoli habbiano quel titolo : Con la tauola copiosissima, & altre cose notabili, che nella prima impressione non erano

Contiene con portada propia: Della descritione del Regno di Napoli ... Libro secondo. In Napoli : Nella Stamperia dello Stigliola à Porta Reale, 1597