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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An alpha-amylase gene from Streptomyces sp WL6 was cloned on a 3.1kb DNA fragment, which was completely sequenced. The 3088 nucleotide sequence obtained contains three putative coding regions in the same orientation. The one corresponding to the structural region of the alpha-amylase gene has a deduced amino acid sequence of 459 residues, showing up to 71% identity to other alpha-amylases. An incomplete ORF was identified upstream the alpha-amylase gene, and the deduced product presents some homology to proteins involved in catabolic regulation.
Biochem Mol Biol Int 1995 Apr
PMID:Cloning and characterization of an alpha-amylase gene from Streptomyces sp WL6. 754 24

Complete sequence-specific assignments of the 1H-NMR spectrum of a fusion protein of the alpha-amylase inhibitor tendamistat from Streptomyces tendae and the activation domain of Tat from human immunodeficiency virus type 1 (HIV-1) was obtained by homonuclear two-dimensional NMR methods. The protein behaves as expected for an ideal fusion protein: the flexible linker allows an almost completely decoupled motion of the subunits of the protein and the two subunits show almost no mutual interaction. In the tendamistat part, small structural distortions due to exchange of the carboxy-terminal leucine propagate mainly via the hydrogen bonds of the beta-sheet and the disulfide bond. The Tat part of the protein contains the seven cysteine residues of full-length Tat. The fusion protein was expressed in Streptomyces lividans and exported. During the export to the extracellular space disulfide bonds are created by the expressing cells, only one sulfhydryl group remains accessible for sulfhydryl reagents. Although a unique, dominant conformation with a specific disulfide bonding pattern exists, a significant conformational variation can be observed including cis-proline peptide bonds, which may indicate smaller populations with alternative disulfide bonding patterns.
J Mol Biol 1995 Jul 28
PMID:Complete 1H nuclear magnetic resonance assignments and structural characterization of a fusion protein of the alpha-amylase inhibitor tendamistat with the activation domain of the human immunodeficiency virus type 1 Tat protein. 762 84

The alpha-amylase (Amy) multigene family in Drosophila pseudoobscura is located on the third chromosome, which is polymorphic for more than 40 inverted gene arrangements. The number of copies in this family ranges from one to three, depending on the arrangement in question. A previous study of the three Amy genes from the Standard (ST) arrangement suggested either that duplicated copies (Amy2 and Amy3) are functionally constrained or that they are undergoing gene conversion with Amy1. In order to elucidate further the pattern of molecular evolution in this family, we cloned and sequenced four additional Amy genes, two from the Santa Cruz (SC) and two from the Chiricahua (CH) gene arrangement. Of the two alternatives, only the hypothesis of gene conversion is supported by the sequence analysis. The homogenization effect of gene conversion has been strongest in SC, whose copies differ by only two nucleotides, less noticeable in ST, and negligible in the CH. Furthermore, the action of gene conversion is apparently localized, occurring only in the coding region. Interestingly, these results concur with the findings of other workers for the duplicated Amy genes in the Drosophila melanogaster group. Thus, the occurrence of gene conversion in the Amy multigene family seems to be a common feature in the Drosophila species studied so far.
Mol Biol Evol 1995 Jul
PMID:Evidence for gene conversion in the amylase multigene family of Drosophila pseudoobscura. 765 12

An alpha-amylase was purified from the solid cultural extract of Aspergillus oryzae ATCC 76080 by sequential steps of amylopectin affinity adsorption, DEAE-Sepharose ion-exchange chromatography and Sephacryl S-200 HR gel filtration. By these steps, the purity of the enzyme increased by 16 fold and recovery of the enzyme activity was 45%. The purified enzyme had an optimal pH between 4 to 5, optimal temperature at 50 degrees C and a Km value of 0.22% for hydrolysis of starch. About 80% of the enzyme activity was lost after incubation at 50 degrees C for 30 min. The heat denaturation constant at 50 degrees C was 0.024 min-1. The molecular weight was 52 kDa as determined by gel filtration. Mercuric ion (0.3 mM), DNFB# (6 mM), NBSI (6 mM) and NAI (6 mM) inhibited the activity of the enzyme. The main products for hydrolysis of maltoheptaose by the enzyme were maltotriose and maltotetraose.
Biochem Mol Biol Int 1995 May
PMID:Purification and properties of alpha-amylase from Aspergillus oryzae ATCC 76080. 766 14

Genomic and two novel cDNA clones for rice seed allergenic protein (RA) belonging to the alpha-amylase/trypsin inhibitor family were isolated and their nucleotide sequences determined. Ten cysteine residues deduced from nucleotide sequences were completely conserved among three cDNA clones including a clone, RA17, reported previously. One genomic clone, lambda 4, contained two RA genes, RAG1 and RAG2. Although RAG1 was cloned at the 5' portion only, two RA genes were arranged divergently. Nucleotide sequencing and DNA blotting analyses showed that RA are encoded by a multigene family consisting of at least four members. The transcriptional initiation site of RAG1 was localized at A, 26 bp upstream of the putative translational initiation codon, ATG, by the primer extension assay. The putative TATA box and CAAT box existed about 45 bp and 147 bp upstream of the transcription initiation site, respectively. A conserved sequence (ATGCAAAA) which was similar to the sequence (TGCAAAA) identified in rice glutelin promoters was observed in the 5' region of the two genes. In addition, RNA blotting analyses provided that RA genes specifically expressed in ripening seed and their transcripts accumulated maximally between 15 and 20 days after flowering.
Plant Mol Biol 1993 Jan
PMID:Gene structure and expression of rice seed allergenic proteins belonging to the alpha-amylase/trypsin inhibitor family. 767 65

With the program FANTOM, we study the effect of a solvation energy term modelled by four atomic solvation parameter sets on energy refinement of proteins. Two parameter sets had previously been derived from measured free energies of transfer of hydrocarbons and amino acid side-chain analogues. Alternatively, the other two parameter sets correspond to the total or apolar accessible surface area of the protein. Twenty-five conformations of BPTI and the alpha-amylase inhibitor tendamistat were refined with respect to empirical energy terms (ECEPP/2) plus a solvation energy term modelled by one of the four atomic solvation parameter sets. These minimizations were compared to minimizations of the ECEPP/2 energy alone with regard to violations of upper distance limits obtained from NMR experiments as well as to root mean square deviations to NMR structures. We find that minimizations of the ECEPP/2 energy plus the total or apolar accessible surface area are superior to minimizations of the ECEPP/2 energy alone. In contrast, minimization of the ECEPP/2 energy plus a solvation energy term based on free energies of transfer perform poorly.
J Mol Biol 1993 Sep 20
PMID:Surface area included in energy refinement of proteins. A comparative study on atomic solvation parameters. 769 Aug 55

Intracellular pH (pHi) of barley aleurone cells is known to be affected by hormones and plant growth conditions. The possible mechanisms by which these pHi shifts influence the actions of abscisic acid (ABA) or gibberellin (GA) is being investigated. Here we report an attempt to study the effect of pHi on hormone-induced gene expression. We used weak acids and weak bases to artificially mimic the pHi changes brought about by ABA and GA and found that chloramphenicol acetyltransferase (CAT) expression controlled by the Rab promoter was affected while the alpha-amylase promoter seemed insensitive. CAT fused to the 35S promoter was used as a control which is not inducible by ABA or GA3. The expression of this construct was not significantly affected by artificial pHi changes.
Plant Mol Biol 1995 Feb
PMID:The effect of intracellular pH on the regulation of the Rab 16A and the alpha-amylase 1/6-4 promoter by abscisic acid and gibberellia. 772 58

The effect of chemical modification of lysine residues on the activity of porcine pancreatic alpha-amylase (PPA) was examined, using p-nitrophenyl-alpha-D-maltoside, p-nitrophenyl-alpha-D-maltotrioside, phenyl-alpha-D-maltoside and phenyl-alpha-D-maltotrioside as substrates. Chemical modification of PPA with trinitrobenzenesulfonic acid enhanced the kcat/Km values for p-nitrophenyl substrates, but not for phenyl substrates. Thus, this effect is substituent selective. Considering the productive binding modes of substrates to PPA, the p-nitro group of the substrate and the modified lysine residues of the enzyme would non-ionically interact with each other to stabilize the productive binding mode.
Biochem Mol Biol Int 1995 Jan
PMID:Effect of a p-nitro group of phenyl-maltooligosaccharide substrate on the change of action specificity of lysine-modified porcine pancreatic alpha-amylase. 773 42

The common bean, Phaseolus vulgaris, contains a family of defense proteins that comprises phytohemagglutinin (PHA), arcelin, and alpha-amylase inhibitor (alpha AI). Here we report eight new derived amino acid sequences of genes in this family obtained with either the polymerase chain reaction using genomic DNA, or by screening cDNA libraries made with RNA from developing beans. These new sequences are: two alpha AI sequences and arcelin-4 obtained from a wild accession of P. vulgaris that is resistant to the Mexican bean weevil (Zabrotes subfasciatus) and the bean weevil (Acanthoscelides obtectus); an alpha AI sequence from the related species P. acutifolius (tepary bean); a PHA and an arcelin-like sequence from P. acutifolius; an alpha AI-like sequence from P. maculatus; and a PHA sequence from an arcelin-5 type P. vulgaris. A dendrogram of 16 sequences shows that they fall into the three identified groups: phytohemagglutinins, arcelins and alpha AIs. A comparison of these derived amino acid sequences indicates that one of the four amino acid residues that is conserved in all legume lectins and is required for carbohydrate binding is absent from all the arcelins; two of the four conserved residues needed for carbohydrate binding are missing from all the alpha AIs. Proteolytic processing at an Asn-Ser site is required for the activation of alpha AI, and this site is present in all alpha AI-like sequences; this processing site is also found at the same position in certain arcelins, which are not proteolytically processed. The presence of this site is therefore not sufficient for processing to occur.
Plant Mol Biol 1994 Nov
PMID:Evolutionary relationships among proteins in the phytohemagglutinin-arcelin-alpha-amylase inhibitor family of the common bean and its relatives. 781 69

Amino acid sequences for three members (CMx1, CMx2, and CMx3) of a new subfamily of trypsin/alpha-amylase inhibitors in wheat have been deduced from the nucleotide sequences of the corresponding cDNAs. A cDNA clone encoding CMx1 was selected from a wheat developing endosperm library using a probe that encoded barley trypsin inhibitor BTI-CMe at low stringency. Sequences corresponding to CMx2 and CMx3 were obtained from cDNA amplified by the polymerase chain reaction. The three CMx sequences contain a premature stop codon after 363 nt, as well as a second stop codon at the same position as in BTI-CMe (nt 439-441). Southern analysis of DNAs from diploid, tetraploid, and hexaploid wheats, as well as from aneuploid lines, indicate that there is a single CMx locus in each of the three genomes of hexaploid wheat, respectively associated with chromosomal arms 4AS, 4BS, and 4DL. These genes are expressed early during endosperm development and not expressed at detectable levels in other tissues. Evolutionary implications are discussed.
Plant Mol Biol 1994 Nov
PMID:Sharp divergence between wheat and barley at loci encoding novel members of the trypsin/alpha-amylase inhibitors family. 781 82


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