scholarly journals Structure-Function Relationships of Glucansucrase and Fructansucrase Enzymes from Lactic Acid Bacteria

2006 ◽  
Vol 70 (1) ◽  
pp. 157-176 ◽  
Author(s):  
Sacha A. F. T. van Hijum ◽  
Slavko Kralj ◽  
Lukasz K. Ozimek ◽  
Lubbert Dijkhuizen ◽  
Ineke G. H. van Geel-Schutten
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Molecular Mass ◽  
Catalytic Domain ◽  
Structural Information ◽  
Protein Structures ◽  
Three Dimensional ◽  
Structural Features ◽  
Product Specificity ◽  
Gram Positive Bacteria

SUMMARY Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase genes and enzymes from various LAB and their fructan and α-glucan products is reviewed. The GS and FS enzymes are both glycoside hydrolase enzymes that act on the same substrate (sucrose) and catalyze (retaining) transglycosylation reactions that result in polysaccharide formation, but they possess completely different protein structures. GS enzymes (family GH70) are large multidomain proteins that occur exclusively in LAB. Their catalytic domain displays clear secondary-structure similarity with α-amylase enzymes (family GH13), with a predicted permuted (β/α)8 barrel structure for which detailed structural and mechanistic information is available. Emphasis now is on identification of residues and regions important for GS enzyme activity and product specificity (synthesis of α-glucans differing in glycosidic linkage type, degree and type of branching, glucan molecular mass, and solubility). FS enzymes (family GH68) occur in both gram-negative and gram-positive bacteria and synthesize β-fructan polymers with either β-(2→6) (inulin) or β-(2→1) (levan) glycosidic bonds. Recently, the first high-resolution three-dimensional structures have become available for FS (levansucrase) proteins, revealing a rare five-bladed β-propeller structure with a deep, negatively charged central pocket. Although these structures have provided detailed mechanistic insights, the structural features in FS enzymes dictating the synthesis of either β-(2→6) or β-(2→1) linkages, degree and type of branching, and fructan molecular mass remain to be identified.

Detection and characterization of a bacteriocin produced by Lactobacillus plantarum C19

1993 ◽  
Vol 39 (12) ◽  
pp. 1173-1179 ◽  
Author(s):  
A. Atrih ◽  
N. Rekhif ◽  
J. B. Milliere ◽  
G. Lefebvre
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Molecular Mass ◽  
Key Words ◽  
Lactobacillus Plantarum ◽  
Resistant Bacteria ◽  
Acidic Ph ◽  
Gram Positive Bacteria ◽  
Ph Dependent

Strain C19, isolated from fermented cucumbers and identified as Lactobacillus plantarum, produced a bacteriocin. This bacteriocin, named plantaricin C19, was stable at acidic pH, was relatively thermostable, and had a molecular mass of about 3.5 kDa. It inhibited some pathogenic (i.e., Listeria spp.) and spoilage Gram-positive bacteria but had weak or no action against lactic acid bacteria. Its adsorption on sensitive and resistant bacteria was pH dependent and was reduced by pretreatment of cells with lipase or lysozyme. Curing treatments with acriflavine or novobiocin yielded nonproducing mutants sensitive to plantaricin C19.Key words: lactic acid bacteria, Lactobacillus plantarum, bacteriocin, protein.

scholarly journals Antibacterial Activity of Some Lactic Acid Bacteria Isolated from an Algerian Dairy Product

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Abdelkader Mezaini ◽  
Nour-Eddine Chihib ◽  
Abdelkader Dilmi Bouras ◽  
Naima Nedjar-Arroume ◽  
Jean Pierre Hornez
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antibacterial Effect ◽  
Dairy Product ◽  
Streptococcus Thermophilus ◽  
Fermented Food ◽  
Bacteriocin Production ◽  
Gram Positive ◽  
Bacteria Growth ◽  
Gram Positive Bacteria

In the present study, the antibacterial effect of 20 lactic acid bacteria isolates from a traditional cheese was investigated. 6 isolates showed antibacterial effect against Gram positive bacteria.Streptococcus thermophilusT2 strain showed the wide inhibitory spectrum against the Gram positive bacteria. Growth and bacteriocin production profiles showed that the maximal bacteriocin production, byS. thermophilusT2 cells, was measured by the end of the late-log phase (90 AUml−1) with a bacteriocine production rate of 9.3 (AUml−1)h−1. In addition, our findings showed that the bacteriocin, produced byS. thermophilusT2, was stable over a wide pH range (4–8); this indicates that such bacteriocin may be useful in acidic as well as nonacidic food. This preliminarily work shows the potential application of autochthonous lactic acid bacteria to improve safety of traditional fermented food.

The First Intrinsic Tenase Complex Inhibitor with Serine Protease Structure Offers a New Perspective in Anticoagulant Therapy

2018 ◽  
Vol 118 (10) ◽  
pp. 1713-1728 ◽  
Author(s):  
Zorica Latinović ◽  
Adrijana Leonardi ◽  
Lidija Kovačič ◽  
Cho Koh ◽  
Jernej Šribar ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Serine Protease ◽  
Blood Coagulation ◽  
Three Dimensional ◽  
Serine Proteinase ◽  
Medical Application ◽  
Structural Features ◽  
Coagulation System ◽  
Three Dimensional Model ◽  
Excessive Bleeding

AbstractComponents of the intrinsic blood coagulation pathway, among them factor VIIIa (FVIIIa), have been recognized as suitable therapeutic targets to treat venous thromboembolism, pathological process behind two very serious cardiovascular diseases, deep vein thrombosis and pulmonary embolism. Here, we describe a unique glycoprotein from the nose-horned viper (Vipera ammodytes ammodytes [Vaa]) venom, Vaa serine proteinase homolog 1 (VaaSPH-1), structurally a serine protease but without an enzymatic activity and expressing potent anticoagulant action in human blood. We demonstrated that one of its targets in the blood coagulation system is FVIIIa of the intrinsic tenase complex, where it antagonizes the binding of FIXa. Anticoagulants with such characteristics are intensively sought, as they would be much safer for medical application as the contemporary drugs, which frequently induce excessive bleeding and other complications. VaaSPH-1 is unlikely to be orally available for chronic usage as it has molecular mass of 35 kDa. However, it represents a very promising template to design low molecular mass FVIIIa-directed anticoagulant substances, based on structural features of the interaction surface between VaaSPH-1 and FVIIIa. To this end, we constructed a three-dimensional model of VaaSPH-1 bound to FVIIIa. The model exposes the 157–loop and the preceding α-helix as the most appropriate structural elements of VaaSPH-1 to be considered as a guideline to synthesize small FVIIIa-binding molecules, potential new generation of anticoagulants.

scholarly journals Protein Structure Determination in Living Cells

2019 ◽  
Vol 20 (10) ◽  
pp. 2442 ◽  
Author(s):  
Teppei Ikeya ◽  
Peter Güntert ◽  
Yutaka Ito
Keyword(s):  
Protein Structure ◽  
Structure Determination ◽  
Structure Prediction ◽  
Structural Information ◽  
Nuclear Overhauser Effect ◽  
Protein Structures ◽  
Three Dimensional ◽  
Structural Data ◽  
Sample Tube ◽  
In Cells

To date, in-cell NMR has elucidated various aspects of protein behaviour by associating structures in physiological conditions. Meanwhile, current studies of this method mostly have deduced protein states in cells exclusively based on ‘indirect’ structural information from peak patterns and chemical shift changes but not ‘direct’ data explicitly including interatomic distances and angles. To fully understand the functions and physical properties of proteins inside cells, it is indispensable to obtain explicit structural data or determine three-dimensional (3D) structures of proteins in cells. Whilst the short lifetime of cells in a sample tube, low sample concentrations, and massive background signals make it difficult to observe NMR signals from proteins inside cells, several methodological advances help to overcome the problems. Paramagnetic effects have an outstanding potential for in-cell structural analysis. The combination of a limited amount of experimental in-cell data with software for ab initio protein structure prediction opens an avenue to visualise 3D protein structures inside cells. Conventional nuclear Overhauser effect spectroscopy (NOESY)-based structure determination is advantageous to elucidate the conformations of side-chain atoms of proteins as well as global structures. In this article, we review current progress for the structure analysis of proteins in living systems and discuss the feasibility of its future works.

scholarly journals Prediction and Analysis of Surface Hydrophobic Residues in Tertiary Structure of Proteins

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Shambhu Malleshappa Gowder ◽  
Jhinuk Chatterjee ◽  
Tanusree Chaudhuri ◽  
Kusum Paul
Keyword(s):  
Tertiary Structure ◽  
Structural Information ◽  
Solvent Accessibility ◽  
Conservation Score ◽  
Protein Structures ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Data Set ◽  
Hydrophobic Residues ◽  
Monomeric Proteins

The analysis of protein structures provides plenty of information about the factors governing the folding and stability of proteins, the preferred amino acids in the protein environment, the location of the residues in the interior/surface of a protein and so forth. In general, hydrophobic residues such as Val, Leu, Ile, Phe, and Met tend to be buried in the interior and polar side chains exposed to solvent. The present work depends on sequence as well as structural information of the protein and aims to understand nature of hydrophobic residues on the protein surfaces. It is based on the nonredundant data set of 218 monomeric proteins. Solvent accessibility of each protein was determined using NACCESS software and then obtained the homologous sequences to understand how well solvent exposed and buried hydrophobic residues are evolutionarily conserved and assigned the confidence scores to hydrophobic residues to be buried or solvent exposed based on the information obtained from conservation score and knowledge of flanking regions of hydrophobic residues. In the absence of a three-dimensional structure, the ability to predict surface accessibility of hydrophobic residues directly from the sequence is of great help in choosing the sites of chemical modification or specific mutations and in the studies of protein stability and molecular interactions.

Models of the Bouguer gravity and geologic structure at Yucca Flat, Nevada

Geophysics ◽  
1988 ◽  
Vol 53 (2) ◽  
pp. 231-244 ◽  
Author(s):  
John F. Ferguson ◽  
Roger N. Felch ◽  
Carlos L. V. Aiken ◽  
John S. Oldow ◽  
Holly Dockery
Keyword(s):  
Structural Information ◽  
Three Dimensional ◽  
Structural Features ◽  
Bouguer Gravity ◽  
Three Dimensional Model ◽  
Geologic History ◽  
The West ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

The Bouguer gravity anomaly at Yucca Flat, Nevada, has been modeled by two different techniques: the Cordell‐Henderson and Parker‐Oldenburg methods. The three‐dimensional model has incorporated known density and structural information where possible. These models predict the structural relief on the Cenozoic‐Paleozoic contact to within 150 m or about 15 percent of the actual depth. The three‐dimensional Parker‐Oldenburg method has been found to be efficient in an application involving a large (9000 sample) data base. Numerical stability was ensured by the application of a consistent regularization (a low‐pass filter tuned to suppress the noise‐dominated portion of the data spectrum) of the downward continuation operator. The use of a single regularizing filter for the entire model is not completely satisfactory due to the oversmoothing of shallow regions of the basin. The model is useful in the delineation of the geologic history of the area. Structural features in the model support the hypothesis that regional stress fields rotated significantly during the Tertiary. Major structural elements of the basin are well defined on the Cenozoic‐Paleozoic interface. The principal basin‐bounding fault is the large‐throw Carpetbag fault on the west. This fault was most active during the earliest phases of subsidence. The Yucca fault is seen to be a much smaller feature in the model presented here. The basin is rotated down to the west, with normal hinge faults on the eastern margin.

scholarly journals Distribution and antimicrobial activity of lactic acid bacteria associated with lychee fruits

2020 ◽  
Vol 25 (6) ◽  
pp. 2079-2085
Author(s):  
LIN-HU NAN ◽  
◽  
YI-SHENG CHEN ◽  
HUI-CHUNG WU ◽  
YU-CHING SU ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
Novel Species ◽  
16S Rrna Gene Sequencing ◽  
Mass Spectrometry Analysis ◽  
Rrna Gene ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Rrna Gene Sequencing

Lychee is a popular fruit in China and southeastern Asia. Although it is very popular, the microbiota of lactic acid bacteria (LAB) associated with lychee remains poorly described. Lychee samples from seven different markets located in three cities in Taiwan were collected and a total of 104 LAB were isolated. Through RFLP analyses of 16S rDNA and rpoA genes for grouping and 16S rRNA gene sequencing, these isolates were finally divided into 6 groups (A to F). The most common genera of LAB in lychee samples were Weissella and Leuconostoc. Weissella confusa strain E was found to produce a bacteriocin active against Listeria monocytogenes and some other Gram-positive bacteria. Mass spectrometry analysis revealed the bacteriocin mass to be approximately 3426.77 Da, which is different to other known Weissella bacteriocins. In addition, strain MB7 included in the genus Leuconostoc was identified as potential novel species or subspecies on the basis of phylogenetic analysis of 16S rRNA, rpoA and pheS gene sequences. Thus, this is the first report describing the distribution and varieties of LAB associated with lychee fruits. In addition, one potential novel LAB species or subspecies and one potential novel bacteriocin were also reported in this study.

scholarly journals UJI ANTIBAKTERI DARI BAKTERI ASAM LAKTAT HASIL FERMENTASI SELADA ROMAIN (Lactuca sativa var. longifolia Lam.)

PHARMACON ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 306
Author(s):  
Acika Sumual ◽  
Fatimawali Fatimawali ◽  
Trina E. Tallei
Keyword(s):  
Antibacterial Activity ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactuca Sativa ◽  
Romaine Lettuce ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Facultative Anaerobes

ABSTRACTLactic Acid Bacteria (LAB) are a group of Gram-positive bacteria that produce lactic acid as the major metabolic end product. They are cocci or rods, nonsporulating and are anaerobic or facultative anaerobes bacteria. Most LABs are probiotics that are known to have good benefits to health, such as inhibiting some pathogens. This study was aimed to examine the potential probiotics properties of LAB isolates from Romaine lettuce fermentation which is included  antibacterial activity of isolates. The isolates are spread on MRS agar  supplemented with 1% of CaCO3 and then purified by using streak method to obtain pure isolates. The results showed that there are 4 isolates from Romaine lettuce fermentation which have the potential to inhibits some pathogens.Key words: Lactic acid bacteria, fermentation, Romain lettuce, potential probiotic ABSTRAKBakteri Asam Laktat (BAL) merupakan sekelompok bakteri Gram positif yang menghasilkan asam laktat sebagai produk akhir metabolisme. Berbentuk kokus atau batang, tidak memiliki spora dan bersifat anaerob atau fakultatif anaerob. Sebagian besar BAL merupakan probiotik yang diketahui memiliki manfaat baik bagi kesehatan, seperti memiliki aktivitas antibakteri. Penelitian ini bertujuan untuk menguji kemampuan isolat BAL dari hasil fermentasi selada Romain sebagai probiotik potensial yang mencakup aktivitas antibakteri isolat. Isolat bakteri ditumbuhkan pada media MRS agar  yang ditambahkan 1% CaCO3 kemudian dimurnikan menggunakan metode gores (streak) sehingga diperoleh isolat murni yang kemudian diuji. Hasil penelitian menunjukkan bahwa ke empat isolat yang diperoleh dari hasil fermentasi selada romain yang berpotensi memiliki aktivitas penghambatan bakteri patogenKata kunci: Bakteri asam laktat, fermentasi, selada Romain, probiotik potensial

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