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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
This method describes the use of subtilisin-catalyzed peptide condensation to form a 15-residue glycopeptide from two smaller synthetic peptides. A 12-residue peptide ester is synthesized by solid-phase peptide synthesis using a
PAM
-modified Rink amide resin that allows the formation of a peptide ester suitable for subtilisin ligation. The 12-residue acyl donor peptide ester is then ligated to a 3-residue acyl acceptor glycopeptide amide using subtilisin (EC 3.4.21.62) in a buffered mixture of water and DMF (1:9).
Methods
Mol
Biol 2004
PMID:Subtilisin-catalyzed glycopeptide condensation. 1519 18
Many phylogenetic inference methods are based on Markov models of sequence evolution. These are usually expressed in terms of a matrix (Q) of instantaneous rates of change but some models of amino acid replacement, most notably the
PAM
model of Dayhoff and colleagues, were originally published only in terms of time-dependent probability matrices (P(t)). Previously published methods for deriving Q have used eigen-decomposition of an approximation to P(t). We show that the commonly used value of t is too large to ensure convergence of the estimates of elements of Q. We describe two simpler alternative methods for deriving Q from information such as that published by Dayhoff and colleagues. Neither of these methods requires approximation or eigen-decomposition. We identify the methods used to derive various different versions of the Dayhoff model in current software, perform a comparison of existing and new implementations, and, to facilitate agreement among scientists using supposedly identical models, recommend that one of the new methods be used as a standard.
Mol
Biol Evol 2005 Feb
PMID:Different versions of the Dayhoff rate matrix. 1548 31
Peptidylglycine alpha-amidating monooxygenase (
PAM
;
EC 1.14.17.3
) catalyzes the COOH-terminal alpha-amidation of peptidylglycine substrates, yielding amidated products. We have previously reported a putative regulatory RNA binding protein (
PAM
mRNA-BP) that binds specifically to the 3' untranslated region (UTR) of
PAM
-mRNA. Here, the
PAM
mRNA-BP was isolated and revealed to be La protein using affinity purification onto a 3' UTR
PAM
RNA, followed by tandem mass spectrometry identification. We determined that the core binding sequence is approximately 15-nucleotides (nt) long and is located 471 nt downstream of the stop codon. Moreover, we identified the La autoantigen as a protein that specifically binds the 3' UTR of
PAM
mRNA in vivo and in vitro. Furthermore, La protein overexpression caused a nuclear retention of
PAM
mRNAs and resulted in the down-regulation of endogenous
PAM
activity. Most interestingly, the nuclear retention of
PAM
mRNA is lost upon expressing the La proteins that lack a conserved nuclear retention element, suggesting a direct association between
PAM
mRNA and La protein in vivo. Reporter assays using a chimeric mRNA that combined luciferase and the 3' UTR of
PAM
mRNA demonstrated a decrease of the reporter activity due to an increase in the nuclear localization of reporter mRNAs, while the deletion of the 15-nt La binding site led to their clear-cut cytoplasmic relocalization. The results suggest an important role for the La protein in the modulation of
PAM
expression, possibly by mechanisms that involve a nuclear retention and perhaps a processing of pre-
PAM
mRNA molecules.
Mol
Cell Biol 2005 Sep
PMID:Mammalian peptidylglycine alpha-amidating monooxygenase mRNA expression can be modulated by the La autoantigen. 1610 99
We employed chlorophyll a fluorometry in order to measure the evolution of turgor threshold (intracellular osmolality) during the adaptation of two genetic transformants of the freshwater cyanobacterium Synechococcus sp. PCC7942 to unfavorable external salinity: PAMCOD cells which oxidize imported choline and accumulate approx. 0.06-0.08 M glycine betaine; and
PAM
cells which do not oxidize choline [Deshnium et al. (1995a) Plant
Mol
Biol 29: 897-909]. Turgor thresholds increased linearly (a) with the NaCl concentration in the culture, and (b) with the molar sucrose/chlorophyll a ratio in the cell. PAMCOD cells could proliferate in culture medium containing 0.4 M NaCl (external osmolality, 0.815 Osm kg(-1)), after a lag period, during which intracellular sucrose rose to 10 mol (mol Chl a)(-1), or more, and turgor threshold (cytoplasmic osmolality) exceeded 1 Osm kg(-1). At comparative conditions,
PAM
cells accumulated approx. half as much sucrose, and attained approx. half as high turgor thresholds as the PAMCOD cells, but they did not proliferate. These results indicate that glycine betaine improved the salinity tolerance of the PAMCOD cells synergistically, by means of two effects that implicate sucrose, the main organic osmolyte of Synechocccus: enhancement of sucrose biosynthesis, and/or alleviation of sucrose toxicity.
...
PMID:Cell turgor: A critical factor for the proliferation of cyanobacteria at unfavorable salinity. 1622 82
A novel core/shell organic nanoparticles, anthracene/poly-acrylamide (AN/
PAM
), has been prepared successfully. Based on the fluorescence quenching of AN/
PAM
nanoparticles by Cr(VI), a method for the selective determination of Cr(VI), without separation of Cr(VI) in water, was developed. Furthermore, the reaction mechanism between nano-AN/
PAM
and Cr(VI) was also discussed. The synthesis and reaction conditions were investigated in detail. The assay is characterized by short reaction time, very few interference stable fluorescence signals, simple instruments and sensitivity. Under optical experimental conditions, a limit of detection of 0.02 microg/ml was achieved. The calibration curve was linear over the concentration range 0.04-2.00 microg/ml with a correlation coefficient of 0.9924. The proposed method has been applied to the selective quantification of Cr(VI) in synthetic samples and waste-water samples with the satisfactory results.
Spectrochim Acta A
Mol
Biomol Spectrosc 2005 Nov
PMID:Preparation and application of a novel core/shell organic nanoparticle as a fluorescence probe in the selective determination of Cr(VI). 1625 60
In an attempt to identify a sensitive and improved marker of mammalian copper status during neonatal development experiments compared two plasma cuproenzymes,
peptidylglycine alpha-amidating monooxygenase
(
PAM
), an enzyme involved in peptide posttranslational activation, to ceruloplasmin (Cp), a ferroxidase involved in iron mobilization. Dietary Cu deficiency (Cu-) was studied in dams and offspring at postnatal age 3 (P3), P12, and P28. Rodent Cp activity rose during lactation whereas
PAM
activity fell. Reduction in Cp activity was more severe than reduction in
PAM
activity in Cu- offspring and dams. Cp activity was greater in rats than mice whereas
PAM
activity was similar in adults but greater in mouse than rat pups. Both cuproenzymes changed during neonatal development and when dietary copper was limiting. With proper controls, each enzyme can be used to assess copper status.
Comp Biochem Physiol B Biochem
Mol
Biol 2006 Mar
PMID:Plasma peptidylglycine alpha-amidating monooxygenase (PAM) and ceruloplasmin are affected by age and copper status in rats and mice. 1644 35
The American Women's Health Initiative study published in July 2002 caused considerable concern among hormone replacement therapy (HRT) users and prescribers in many countries. This study is an exploratory research comparing the genome-wide expression profile in whole-blood samples according to HRT use. Within the Norwegian Women and Cancer study, 100 postmenopausal women (50 HRT users and 50 non-HRT users) born between 1943 and 1949 with normal to high body mass index and no other medication use were selected. After total RNA extraction, amplification, and labeling, the samples were hybridized together with a common reference (Universal human reference RNA, Stratagen) to Agilent Human 1A oligoarrays (G4110b, Agilent Technologies) containing 20,173 unique genes. Differentially expressed genes were used to build a classifier using the nearest shrunken centroid method (
PAM
). Then, we tested the significant changes in single genes by different methods like t test, Significance Analysis of Microarrays, and Bayesian ANOVA analysis. Results did not reveal any distinct gene list which predicted accurately HRT exposure (error rate, 0.40). Classifier performance slightly improved (error rate, 0.26) including only women who were using continuous combined HRT treatment. According to the small amplitude of expression alterations observed in whole blood, more quantitative technique and larger sample sizes will be needed to be able to investigate whether significant single genes are differentially expressed in HRT versus non-HRT users. Taken cautiously, significant enrichments in biological process of genes with small changes after HRT use were observed (e.g., receptor and transporter activities, immune response, frizzled signaling pathway, actin filament organization, and glycogen metabolism).
Mol
Cancer Ther 2006 Apr
PMID:Gene expression profiling of whole-blood samples from women exposed to hormone replacement therapy. 1664 56
Many mitochondrial proteins are encoded by nuclear genes and after translation in the cytoplasm are imported via translocases in the outer and inner membranes, the TOM and TIM complexes, respectively. Here, we report the characterization of the mitochondrial protein, Mmp37p (YGR046w) and demonstrate its involvement in the process of protein import into mitochondria. Haploid cells deleted of MMP37 are viable but display a temperature-sensitive growth phenotype and are inviable in the absence of mitochondrial DNA. Mmp37p is located in the mitochondrial matrix where it is peripherally associated with the inner membrane. We show that Mmp37p has a role in the translocation of proteins across the mitochondrial inner membrane via the TIM23-
PAM
complex and further demonstrate that substrates containing a tightly folded domain in close proximity to their mitochondrial targeting sequences display a particular dependency on Mmp37p for mitochondrial import. Prior unfolding of the preprotein, or extension of the region between the targeting signal and the tightly folded domain, relieves their dependency for Mmp37p. Furthermore, evidence is presented to show that Mmp37 may affect the assembly state of the TIM23 complex. On the basis of these findings, we hypothesize that the presence of Mmp37p enhances the early stages of the TIM23 matrix import pathway to ensure engagement of incoming preproteins with the mtHsp70p/
PAM
complex, a step that is necessary to drive the unfolding and complete translocation of the preprotein into the matrix.
Mol
Biol Cell 2006 Sep
PMID:Characterization of Mmp37p, a Saccharomyces cerevisiae mitochondrial matrix protein with a role in mitochondrial protein import. 1679 Apr 93
The strong fluorescence Tb/acetyl acetone (acac)/Poly (Acrylamide) (
PAM
) composite nanoparticles have been prepared under ultrasonic radiation. The nanoparticles were water-soluble, stable and have extremely narrow emission bands and high internal quantum efficiencies. Based on the fluorescence quenching of Tb/acac/
PAM
by Cr (VI), a method for the selective determination of Cr (VI), without separation of Cr (III) in water, was developed. The reaction condition between Cr (VI) and Tb/acac/
PAM
were investigated in detail. Under optimal experimental conditions, the linear calibration curve was obtained over the concentration range of 5-600 ng mL(-1) with a correlation coefficient of 0.9939. The corresponding detection limit is 0.8 ng mL(-1) and the relative standard deviation is 1.5% for 0.05 microg mL(-1) (n=7). The proposed method has been applied to the selective quantification of Cr (VI) in synthetic samples and waste-water samples with the satisfactory results. The assay is characterized by short reaction time, very few interference, stable fluorescence signals, simple instrument and simplicity.
Spectrochim Acta A
Mol
Biomol Spectrosc 2006 Sep
PMID:Selective fluorescence determination of chromium (VI) in water samples with terbium composite nanoparticles. 1687 37
Available evidence suggests that, in African populations, systemic blood-dwelling parasitoses of mothers are associated with enhanced susceptibility to infection of their offspring. Thus, children born to mothers with filariasis or schistosomiasis are infected earlier, and offspring of mothers with placental Plasmodium falciparum at delivery, commonly referred to as pregnancy-associated malaria or
PAM
, are themselves at higher risk of developing parasitaemia during infancy. Since foetal/neonatal antigen-presenting cells (APC) are either immature or provide insufficient costimulatory signals to T cells, thus favouring tolerance induction, it is commonly assumed that soluble parasite components [protein antigens], transferred transplacentally and inducing foetal immune tolerance, are largely, if not exclusively, responsible for these outcomes. Plasmodial asexual blood stage antigen-specific T cells are detectable in as many as two-thirds of all cord blood samples in malaria-endemic countries of sub-Saharan Africa, indicating that in utero sensitization may be a common phenomenon during pregnancy in these populations. Parasite antigen-specific T cell responses of neonates born to helminth-infected mothers display a highly skewed Th2-type cytokine pattern, with a prominent role for the regulatory cytokine interleukin (IL)-10. Similarly, the cord blood immune response of those born to mothers identified with on-going
PAM
is characterised by inducible parasite antigen-specific IL-10-producing regulatory T cells that can inhibit both APC HLA expression and Th1-type T cell responses. In contrast, plasmodial antigen-specific Th1-type responses, characterised by IFN-gamma production, predominate in cord blood of those born to mothers successfully treated for Pf malaria during gestation, suggesting that the duration and/or the nature of antigen exposure in utero governs the outcome with respect to neonatal immune responses. Aspects of APC function in the context of these differentially modulated responses, whether and how the latter translate into altered susceptibility to Pf infection during infancy, as well as the possible implications for vaccination in early life, are aspects that are discussed in this review.
Mol
Biochem Parasitol 2007 Jan
PMID:Placental Plasmodium falciparum infection: causes and consequences of in utero sensitization to parasite antigens. 1708 34
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