Nautilus hard parts: a study of the mineral and organic constitutents

Paleobiology ◽  
1984 ◽  
Vol 10 (2) ◽  
pp. 268-279 ◽  
Author(s):  
H. A. Lowenstam ◽  
W. Traub ◽  
S. Weiner
Keyword(s):  
Amino Acid ◽  
Isotopic Composition ◽  
Protein Complexes ◽  
Organic Matrix ◽  
Tendon Sheath ◽  
Evolutionary Trend ◽  
X Ray Diffraction ◽  
Shell Wall ◽  
X Ray ◽  
Tube Shell

The mineralized hard parts of Nautilus, including the mandibles, statoconia, and uroliths, are more complex with respect to ultrastructure, mineralogy, trace element, and isotopic composition than was previously recognized. X-ray diffraction and amino acid composition analyses of the organic structural hard parts (siphuncle tube, shell wall and septum organic matrix, mandibles, and muscle tendon sheath) show that two different chitin-protein complexes are utilized by Nautilus. The mandible mineral hard parts are particularly complex, with five different minerals present in various locations. A comparison of the statoconia of Nautilus species with the statoliths of dibranchian cephalopods reveals an evolutionary trend in which carbonate is substituted for phosphate. This study also shows that Nautilus uses a number of different crystal-forming processes for constructing its hard parts. The data presented here provide a broad spectrum of information, which, when applied to the fossil counterparts, can be utilized for improving our understanding of ancient nautiloid biology.

Axially Chiral Bis(α-amino Acid)s and Their Deamino Analogues. Synthesis and Configurational Assignment

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Configurational Assignment ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
Polymeric Structures

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.

scholarly journals Synthesis, characterization, x-ray diffraction studies and biological activities of iron(III) and cobalt(II) complexes with alanine

2018 ◽  
Vol 6 (2) ◽  
pp. 132
Author(s):  
Shuaibu Musa ◽  
S O. Idris ◽  
A D. Onu
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Human Life ◽  
Molar Conductance ◽  
Biological Molecules ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Metal Ligands ◽  
Elemental Analyses

The resulted complexes produced between Fe (III) and Co (II) with biological molecules like amino acids play an important role in human life. They can be used as bioactive compounds as well as in industries. Fe (III) and Co (II) complexes are synthesized with Alanine amino acid. The complexes were characterized by X-ray diffraction, magnetic suscetivility, elemental analysis (AAS), molar conductance, melting point, infrared and uv-visible spectrophotometry analyses. The elemental analyses were used to determine the chelation ratio, 1:3(metal: ligands) for iron (III) Alanine and 1:2 ratio for cobalt (II) Alanine. The molar conductivity of the complexes show that the complexes are not electrolytic in nature. The x-ray data suggest monoclinic crystal system for all the complexes with the exception of Co-alanine, which is hexagonal. The magnetic susceptivility and electronic spectra suggest the complexes are high spin with octahedral geometry.The complexes show enhance activity in comparable to the amino acid.  

scholarly journals HUMAN AMYLOID PROTEIN: CHEMICAL VARIABILITY AND HOMOGENEITY

1971 ◽  
Vol 19 (1) ◽  
pp. 1-15 ◽  
Author(s):  
M. HARADA ◽  
C. ISERSKY ◽  
P. CUATRECASAS ◽  
D. PAGE ◽  
H. A. BLADEN ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amyloid Fibril ◽  
Gel Filtration ◽  
Protein S ◽  
Amyloid Protein ◽  
X Ray Diffraction ◽  
Amyloid Proteins ◽  
X Ray ◽  
Chemical Variability ◽  
Sepharose 4B

The morphology of the fibril of amyloid derived from different individuals is similar, but occasionally significant differences are noted. All human amyloid filaments have a "β-pleated sheet" conformation as revealed by x-ray diffraction, and those examined after orientation show a "cross-β" pattern. All amyloid fibril concentrates studied so far can be fractionated to obtain the major amyloid protein component(s) by sequential gel filtration with 5 M guanidine-HCl in 1 N acetic acid on Sepharose 4B and Sephadex G-100 or G-75 columns with the removal of over 28% of proteins representing minor constituents. The major amyloid protein(s) obtained from the spleen and/or liver of six patients is found to contain tryptophan, to be deficient in hydroxylysine and hydroxyproline and usually at least one commonly occurring amino acid and to have a high content of dicarboxylic acid and short chain amino acids and unreactive (blocked) NH2-terminal groups or aspartic acid-asparagine (Asx). However, the amyloid protein(s) from each individual differs from that of the others in molecular weight, in amino acid composition and in the presence or absence of specific tryptic peptides. Amyloid protein(s) from the liver and spleen of the same individual is identical. No chemical characteristics distinguish amyloid proteins derived from cases classified clinically as "primary" from those classified as "secondary." There is a striking chemical similarity between amyloid proteins and the NH2-terminal variable fragment of the light and heavy chain of immumoglobulin proteins.

Elucidation of the two-dimensional structure of an α-amino acid surfactant monolayer on water using synchrotron X-ray diffraction

Nature ◽  
1987 ◽  
Vol 328 (6125) ◽  
pp. 63-66 ◽  
Author(s):  
Sharon Grayer Wolf ◽  
Leslie Leiserowitz ◽  
Meir Lahav ◽  
Moshe Deutsch ◽  
Kristian Kjaer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Clay intercalated Cu(II) amino acid complexes: synthesis, spectroscopy and catalysis

Clay Minerals ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 491-500 ◽  
Author(s):  
L. Fu ◽  
B. M. Weckhuysen ◽  
A. A. Verberckmoes ◽  
R. A. Schoonheydt
Keyword(s):  
Amino Acid ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
The Novel ◽  
Oxidation Reactions ◽  
Axially Symmetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spin Resonance ◽  
Synthesized Materials

AbstractComplexes of Cu(lysine)2+2 and Cu(histidine)2+2 have been intercalated between the layers of saponite clays by a simple cation exchange procedure from aqueous solutions of preformed Cu(amino acid)2-complexes. Successful immobilization was obtained with an amino acid: Cu2+ ratio of 5, and a pH of 10 and 7.3 for lysine and histidine, respectively. The synthesized materials were investigated as powders and as thin films by electron spin resonance (ESR), diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). The light blue clays are characterized by an axially symmetric ESR spectrum with A//= 192 G, g//= 2.23 and g⊥ = 2.07, and a d-d absorption band around 600 nm, due to the intercalated planar Cu2+-complexes. Ammonia interacts reversibly with these intercalated complexes, suggesting the presence of a free coordination site. The novel synthesized materials are active in various oxidation reactions with t-butyl hydroperoxide as oxidant.

Metallkomplexe mit biologisch wichtigen Liganden, CXV. Addition von α-Aminosäureestern an [CpFe(CO)3]+: Carbamoylkomplexe Cp(OC)2Fe-C(O)NHCHRCO2R’ und Kristallstruktur von Cp(OC)2Fe-C(O)NHCH2CO2Et / Metal Complexes of Biologically Important Ligands, CXV. Addition of α-Amino Acid Esters to [CpFe(CO)3]+: Carbamoyl Complexes Cp(OC)2Fe-C(O)NHCHRCO2R' and Crystal Structure of Cp(OC)2Fe-C(O)NHCH2CO2Et

1999 ◽  
Vol 54 (3) ◽  
pp. 385-388 ◽  
Author(s):  
Reinhold Urban ◽  
Kurt Polbom ◽  
Wolfgang Beck
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Metal Complexes ◽  
Amino Acid Esters ◽  
X Ray Diffraction ◽  
Carbonyl Ligand ◽  
X Ray ◽  
Acid Esters

α-Amino acid esters can be added to a carbonyl ligand of [CpFe(CO)3]+CF3SO3- to give the carbamoyl complexes Cp(OC)2Fe-C(O)NHCHRCO2R′ (R = H, Me, CHMe2, CH2Ph; R′ = Et, Me). This type of reaction may be useful for the marking of peptides at the amino end. The crystal structure of Cp(OC)2Fe-C(O)NHCH2CO2Et was determined by X-ray diffraction.

Expression, crystallization and preliminary X-ray diffraction studies ofN-carbamyl-D-amino-acid amidohydrolase fromAgrobacterium radiobacter

1999 ◽  
Vol 55 (3) ◽  
pp. 694-695 ◽  
Author(s):  
Wen-Hwei Hsu ◽  
Fan-Tso Chien ◽  
Chuan-Long Hsu ◽  
Tse-Chi Wang ◽  
Hanna S. Yuan ◽  
...  
Keyword(s):  
Amino Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Amidohydrolase
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