Tetra-n-butylammonium bromide forms the title semi-clathrate hydrate crystal, C16H36N+.Br-.38H2O, under atmospheric pressure. The cation and anion lie at sites with mm symmetry seven water molecules m in space group Pmma. Br- anions construct a cage structure molecules. cations are disordered located centre of four cages, viz. two tetrakaidecahedra pentakaidecahedra ideal structures, while all dodecahedral cages empty.

We used directed evolution to enhance the thermostability of glycosyl hydrolase family-11 xylanase from <i>Bacillus subtilis</i>. By combining random point mutagenesis, saturation and DNA shuffling, a thermostable variant, Xyl^st, was identified which contained three amino acid substitutions: Q7H, N8F, S179C. The half-inactivation temperature (the midpoint melting curves) for Xyl^st variant compared with wild-type enzyme after incubation 10 min elevated 58 68 °C. At 60 °C...

Antifreeze proteins (AFPs) are found in organisms ranging from fish to bacteria, where they serve different functions facilitate survival of their host. AFPs that protect freeze-intolerant and insects internal ice growth bind using a regular array well-conserved residues/motifs. Less is known about the role freeze-tolerant species, which might be beneficially alter structure or around Here we report 0.95-Å high-resolution crystal 223-residue secreted AFP snow mold fungus Typhula...

A total of 71 isolates were collected from lake sediment and soil surrounding lakes in the Skarvsnes area, Antarctica. Based on ITS region sequence similarity, these classified to 10 genera. Twenty-three categorized as ascomycetous fungi five genera (Embellisia, Phoma, Geomyces, Tetracladium or Thelebolus) 48 basidiomycetous (Mrakia, Cryptococcus, Dioszegia, Rhodotorula Leucosporidium). Thirty-five percent culturable genus Mrakia. Eighteen eight selected tested for both antifreeze activity...

Antifreeze proteins (AFPs) are structurally diverse macromolecules that bind to ice crystals and inhibit their growth protect the organism from injuries caused by freezing. An AFP identified Antarctic bacterium Colwellia sp. strain SLW05 (ColAFP) is homologous AFPs a wide variety of psychrophilic microorganisms. To understand antifreeze function ColAFP, we have characterized its activity determined crystal structure this protein. The recombinant ColAFP exhibited thermal hysteresis...

Ice recrystallization is a phenomenon observed as the increase in ice crystal size within an already frozen material. Antifreeze proteins (AFPs), class of capable arresting growth, are known to inhibit this even at sub milli-molar concentrations. A tremendous range possible applications AFPs hence expected both medical and industrial fields, while key determinant inhibition (IRI) hardly understood. Here, IRI efficiency plane affinity were examined for wild-type AFPI-III, defective AFPIII...

The psychrophilic fungi Coprinus psychromorbidus and Typhula ishikariensis produced unique antifreeze proteins (AFPs) in the extracellular space. Molecular masses of purified fungal AFPs C. T. were approximately 22 23 kDa, respectively. Cloned genes from do not have any similarity with known proteins. Purified cultural filtrate recombinant AFP methylotrophic yeast formed specific ice crystals resembling "Stone Age knives". These observations indicate that form proper hexagonal to inhibit...

To investigate the role of Vernier zone residues, which are comprised in framework regions and underlie complementarity-determining (CDRs) antibodies, specific, high affinity interactions antibodies with their targets, we focused on variable domain fragment murine anti-human epidermal growth factor receptor antibody 528 (m528Fv). Grafting CDRs m528Fv onto a selected region human referred to as humanization, reduced antibody's for its target by 1/40. The reduction was due substantial negative...

Antifreeze proteins are structurally diverse polypeptides that have thermal hysteresis activity and been discovered in many cold-adapted organisms. Of these, fungal antifreeze protein has purified partially characterized only a species of psychrophilic basidiomycete, Typhula ishikariensis. Here we report new from another psychrophile, Antarctomyces psychrotrophicus. We examined its biochemical properties activity, compared them with those the T. ishikariensis protein. The A. psychrotrophicus...

Snow mold fungus, Typhula ishikariensis, secretes seven antifreeze protein isoforms (denoted TisAFPs) that assist in the survival of under snow cover. Here, X-ray crystal structure a hyperactive isoform, TisAFP8, at 1.0 Å resolution is presented. TisAFP8 folds into right-handed β-helix accompanied with long α-helix insertion. exhibited significantly high activity comparable other AFPs, despite its close structural and sequence similarity moderately active isoform TisAFP6. A series mutations...

Abstract A supersoluble 40-residue type I antifreeze protein (AFP) was discovered in a righteye flounder, the barfin plaice (bp). Unlike all other AFPs characterized to date, bpAFP transitions from moderately-active hyperactive with increasing concentration. At sub-mM concentrations, bound pyramidal planes of ice shape it into bi-pyramidal hexagonal trapezohedron, similarly AFPs. mM uniquely underwent further binding whole crystal surface including basal planes. The latter caused bursting...

Bacillus subtilis extracellular lipase (BsL) has an exceptionally low molecular weight (19.4 kDa) for a member of the family. A crystallographic study was performed on BsL in order to design and produce mutant that will be more suitable industrial uses based analysis three-dimensional structure. Recently, crystal structure been determined at 1.5 resolution [van Pouderoyen et al. (2001). J. Mol. Biol. 309, 215-226]. In present study, new form which provides diffraction data higher obtained...

A catalase that exhibits a high level of activity and rapid reaction with organic peroxides has been purified from Exiguobacterium oxidotolerans T-2-2T (EKTA catalase). The amino acid sequence EKTA revealed it is novel clade 1 catalase. Amino residues in the active site around protoheme are conserved primary structure Although general interactions molecules larger than hydrogen peroxide catalases strongly inhibited because selection role long narrow channels substrate reaching site,...

The structural and enzymatic characteristics of a cutinase-like enzyme (CLE) from Cryptococcus sp. strain S-2, which exhibits remote homology to lipolytic cutinase the fungus Fusarium solani (FS cutinase), were compared investigate unique substrate specificity CLE. crystal structure CLE was solved 1.05 A resolution. Moreover, hydrolysis assays demonstrated broad for short long-chain substrates, as well preferred FS short-chain substrates. In addition, site-directed mutagenesis performed...

Significance This study expands our knowledge of protein hydration, which is highly related to the macromolecular antifreeze property proteins. We examined a polypentagonal network formation waters for series artificial variants 65-residue ice-binding protein. The were created solely on surface an activity-improved variant, appeared contain two sets water clusters exhibiting perfect position match constructing first prism and pyramidal ice planes. These data suggest that minute structural...

In order to address the recognition mechanism of fragments antibody variable regions, termed Fv, toward their target antigen, an x-ray crystal structure anti-hen egg white lysozyme (HyHEL-10) Fv fragment complexed with its cognate hen (HEL), was solved at 2.3 Å. The overall complex is similar that reported in a previous article dealing Fab fragment-HEL (PDB ID code, 3HFM). However, areas covered by HEL upon formation increased about 100 Ų comparison Fab-HEL complex, and two local...

To study the role of hydrogen bonding via interfacial water molecules in protein-protein interactions, we examined interaction between hen egg white lysozyme (HEL) and its HyHEL-10 variable domain fragment (Fv) antibody. We constructed three antibody mutants (l-Y50F, l-S91A, l-S93A) investigated interactions mutant Fvs HEL. Isothermal titration calorimetry indicated that mutations significantly decreased negative enthalpy change (8–25 kJ mol⁻¹), despite some offset by a favorable...

To clarify the effects of humanizing a murine antibody on its specificity and affinity for target, we examined interaction between hen egg white lysozyme (HEL) antibody, HyHEL-10 variable domain fragment (Fv). We selected human framework sequence with high homology, grafted sequences six complementarity-determining regions onto framework, investigated interactions mutant Fvs HEL. Isothermal titration calorimetry indicated that humanization led to 10-fold reduced due an unfavorable entropy...

Various microbes, including fungi and bacteria, that live in cold environments produce ice‐binding proteins ( IBP s) protect them from freezing. Ascomycota Basidiomycota are two major phyla of fungi, Antarctomyces psychrotrophicus is currently designated as the sole ascomycete produces (Anp ). However, its complete amino acid sequence, property, evolutionary history have not yet been clarified. Here, we determined peptide sequences three new Anp isoforms by total cDNA analysis compared with...