Understanding Magnetite Biomineralisation: The Effect of Short Amino Acid Sequences on the {100} and the {111} Surface

2013 ◽  
Vol 1498 ◽  
pp. 239-245
Author(s):  
Amy E. Monnington ◽  
David J. Cooke
Keyword(s):  
Amino Acid ◽  
Glutamic Acid ◽  
Binding Sites ◽  
Amino Acid Sequences ◽  
Iron Binding ◽  
Binding Ability ◽  
C Terminus ◽  
Amino Acid Repeats ◽  
Magnetospirillum Magneticum ◽  
Magnetite Formation

ABSTRACTMagnetite (Fe3O4) formation within Magnetospirillum magneticum strain AMB-1 occurs under the influence of the Mms6 protein. It is hypothesised that if key iron binding sites within the C-terminus of the Mms6 protein are substituted for alanine, the protein’s overall iron binding ability is diminished. In this study, an atomistic model of Mms6-driven magnetite formation was developed and the attachment of series amino acid repeats (alanine-alanine, alanine-glutamic acid & glutamic acid-glutamic acid) to the {100} & {111} magnetite surfaces were investigated. Our results suggest the substitution of glutamic acid for alanine residues significantly reduces iron binding affinity of the system, thus confirming the hypothesis. In addition, it is shown that the surface of preferable attachment is the {111} magnetite surface.

scholarly journals Identification, characterization and cloning of myr 1, a mammalian myosin-I.

1993 ◽  
Vol 120 (6) ◽  
pp. 1393-1403 ◽  
Author(s):  
C Ruppert ◽  
R Kroschewski ◽  
M Bähler
Keyword(s):  
Amino Acid ◽  
Light Chain ◽  
Brush Border ◽  
Binding Sites ◽  
Neuronal Development ◽  
Amino Acid Sequences ◽  
Dependent Manner ◽  
Tail Domain ◽  
Myosin I ◽  
Splice Forms

We have identified, characterized and cloned a novel mammalian myosin-I motor-molecule, called myr 1 (myosin-I from rat). Myr 1 exists in three alternative splice forms: myr 1a, myr 1b, and myr 1c. These splice forms differ in their numbers of putative calmodulin/light chain binding sites. Myr 1a-c were selectively released by ATP, bound in a nucleotide-dependent manner to F-actin and exhibited amino acid sequences characteristic of myosin-I motor domains. In addition to the motor domain, they contained a regulatory domain with up to six putative calmodulin/light chain binding sites and a tail domain. The tail domain exhibited 47% amino acid sequence identity to the brush border myosin-I tail domain, demonstrating that myr 1 is related to the only other mammalian myosin-I motor molecule that has been characterized so far. In contrast to brush border myosin-I which is expressed in mature enterocytes, myr 1 splice forms were differentially expressed in all tested tissues. Therefore, myr 1 is the first mammalian myosin-I motor molecule with a widespread tissue distribution in neonatal and adult tissues. The myr 1a splice form was preferentially expressed in neuronal tissues. Its expression was developmentally regulated during rat forebrain ontogeny and subcellular fractionation revealed an enrichment in purified growth cone particles, data consistent with a role for myr 1a in neuronal development.

scholarly journals The Extracellular Transport Signal of the Vibrio cholerae Endochitinase (ChiA) Is a Structural Motif Located between Amino Acids 75 and 555

2002 ◽  
Vol 184 (8) ◽  
pp. 2225-2234 ◽  
Author(s):  
Jason P. Folster ◽  
Terry D. Connell
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Vibrio Cholerae ◽  
Structural Information ◽  
Amino Acid Sequences ◽  
Structural Motif ◽  
Terminal Branch ◽  
C Terminus ◽  
N Terminus ◽  
Extracellular Transport

ABSTRACT ChiA, an 88-kDa endochitinase encoded by the chiA gene of the gram-negative enteropathogen Vibrio cholerae, is secreted via the eps-encoded main terminal branch of the general secretory pathway (GSP), a mechanism which also transports cholera toxin. To localize the extracellular transport signal of ChiA that initiates transport of the protein through the GSP, a chimera comprised of ChiA fused at the N terminus with the maltose-binding protein (MalE) of Escherichia coli and fused at the C terminus with a 13-amino-acid epitope tag (E-tag) was expressed in strain 569B(chiA::Kanr), a chiA-deficient but secretion-competent mutant of V. cholerae. Fractionation studies revealed that blockage of the natural N terminus and C terminus of ChiA did not prevent secretion of the MalE-ChiA-E-tag chimera. To locate the amino acid sequences which encoded the transport signal, a series of truncations of ChiA were engineered. Secretion of the mutant polypeptides was curtailed only when ChiA was deleted from the N terminus beyond amino acid position 75 or from the C terminus beyond amino acid 555. A mutant ChiA comprised of only those amino acids was secreted by wild-type V. cholerae but not by an epsD mutant, establishing that amino acids 75 to 555 independently harbored sufficient structural information to promote secretion by the GSP of V. cholerae. Cys77 and Cys537, two cysteines located just within the termini of ChiA(75-555), were not required for secretion, indicating that those residues were not essential for maintaining the functional activity of the ChiA extracellular transport signal.

A Contact Site between the Two Reaction Center Polypeptides of Photosystem II Is Involved in Photoinhibition

1991 ◽  
Vol 46 (7-8) ◽  
pp. 557-562 ◽  
Author(s):  
A. Trebst
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Reaction Center ◽  
Binding Sites ◽  
Cleavage Site ◽  
Amino Acid Sequences ◽  
Contact Site ◽  
Quinone Binding ◽  
Herbicide Binding ◽  
Sensitive Site

Abstract A new contact site between the two reaction center polypeptides D 1 and D 2 of photosystem II close to arg 238 and arg 234 respectively is proposed. The amino acid sequences involved are between the 4 th transmembrane and a connecting parallel helix. The sequence includes a tryp­ sin sensitive site in both polypeptides, the likely cleavage site in the rapid turnover of the D 1 polypeptide and part of the herbicide binding site. The contact site is oriented towards both quinone binding sites Q A and Q B. A folding of the backbone of the amino acid sequences involved is proposed.

scholarly journals Amino acid sequences around the cystine residues in horse growth hormone

1968 ◽  
Vol 109 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Louise Oliver ◽  
Anne Stockell Hartree
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Amino Acid ◽  
Growth Hormones ◽  
Amino Acid Sequences ◽  
The Other ◽  
Published Data ◽  
C Terminus

The cystine-containing peptides of horse growth hormone were isolated and their amino acid sequences determined. Four unique half-cystine residues occur in two peptides, one containing 11 and the other, at the C-terminus of the protein, 15 amino acids. These sequences are compared with published data on growth hormones from other species.

scholarly journals Identification of metal ion binding sites based on amino acid sequences

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183756 ◽  
Author(s):  
Xiaoyong Cao ◽  
Xiuzhen Hu ◽  
Xiaojin Zhang ◽  
Sujuan Gao ◽  
Changjiang Ding ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Sites ◽  
Metal Ion ◽  
Amino Acid Sequences ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Ion Binding Sites ◽  
Metal Ion Binding Sites

scholarly journals Occurrence of PG-Lb, a leucine-rich small chondroitin/dermatan sulphate proteoglycan in mammalian epiphyseal cartilage: molecular cloning and sequence analysis of the mouse cDNA

1996 ◽  
Vol 318 (3) ◽  
pp. 909-914 ◽  
Author(s):  
Kazuhiro KURITA ◽  
Tamayuki SHINOMURA ◽  
Minoru UJITA ◽  
Masahiro ZAKO ◽  
Daihei KIDA ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Amino Acid Sequences ◽  
Epiphyseal Cartilage ◽  
Newborn Mouse ◽  
Dermatan Sulphate ◽  
Cdna Fragment ◽  
Sulphate Proteoglycan ◽  
C Terminus ◽  
Degenerate Oligonucleotide

PG-Lb is a chondroitin/dermatan sulphate proteoglycan first isolated from chick embryo limb cartilage. It had been assumed that osteoglycin represents its mammalian homologue. However, partial amino acid sequences of a novel proteoglycan from bovine epiphyseal cartilage showed high identity with those of chick PG-Lb (P. Neame, L. Rosenberg and M. Höök, personal communication). Reverse transcriptase PCR using degenerate oligonucleotide primers gave a cDNA fragment that might correspond to mouse PG-Lb. We isolated a clone from a cDNA library of newborn mouse epiphyseal cartilage using the cDNA fragment as a probe. The cloned cDNA was 1430 bp long and contained a 966 bp open reading frame which encoded the core protein consisting of 322 amino acid residues. The deduced amino acid sequence showed a high overall identity with chick PG-Lb (about 62%, reaching about 80% over the carboxyl two-thirds). In addition, the amino acid sequence contained a signal peptide, six cysteine residues at the invariant relative position to chick PG-Lb, six leucine-rich repeats at the carboxyl two-thirds, three possible glycosaminoglycan-attachment sites (two sites at the N-terminal side and one site at the C-terminus) and two possible Asn-glycosylation sites near the C-terminus. Northern-blot analysis demonstrated the specific expression of a 1.5 kb message in cartilage and testis. These structural features and the characteristic expression suggest that the cloned molecule is mouse PG-Lb.

scholarly journals Release of Periplasmic Proteins of Brucella suis upon Acidic Shock Involves the Outer Membrane Protein Omp25

2004 ◽  
Vol 72 (10) ◽  
pp. 5693-5703 ◽  
Author(s):  
Rose-Anne Boigegrain ◽  
Imed Salhi ◽  
Maria-Teresa Alvarez-Martinez ◽  
Jan Machold ◽  
Yann Fedon ◽  
...  
Keyword(s):  
Amino Acid ◽  
Brucella Melitensis ◽  
Amino Acid Sequences ◽  
Acetate Buffer ◽  
Citrate Buffer ◽  
Type Iv ◽  
Amino Acid Repeats ◽  
Brucella Suis ◽  
Periplasmic Proteins ◽  
Secretory System

ABSTRACT The survival and replication of Brucella in macrophages is initially triggered by a low intraphagosomal pH. In order to identify proteins released by Brucella during this early acidification step, we analyzed Brucella suis conditioned medium at various pH levels. No significant proteins were released at pH 4.0 in minimal medium or citrate buffer, whereas in acetate buffer, B. suis released a substantial amount of soluble proteins. Comparison of 13 N-terminal amino acid sequences determined by Edman degradation with their corresponding genomic sequences revealed that all of these proteins possessed a signal peptide indicative of their periplasmic location. Ten proteins are putative substrate binding proteins, including a homologue of the nopaline binding protein of Agrobacterium tumefaciens. The absence of this homologue in Brucella melitensis was due to the deletion of a 7.7-kb DNA fragment in its genome. We also characterized for the first time a hypothetical 9.8-kDa basic protein composed of five amino acid repeats. In B. suis, this protein contained 9 repeats, while 12 were present in the B. melitensis orthologue. B. suis in acetate buffer depended on neither the virB type IV secretory system nor the omp31 gene product. However, the integrity of the omp25 gene was required for release at acidic pH, while the absence of omp25b or omp25c displayed smaller effects. Together, these results suggest that Omp25 is involved in the membrane permeability of Brucella in acidic medium.

scholarly journals Serological and fluorescence studies of the heat stability of bovine lactoferrin

1979 ◽  
Vol 46 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Augustin Baer ◽  
Marko Oroz ◽  
Bernard Blanc
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Complement Fixation ◽  
Heat Stability ◽  
Heat Denaturation ◽  
Bovine Lactoferrin ◽  
Iron Binding ◽  
Binding Ability ◽  
Fluorescence Studies ◽  
Tryptophan Residues

SUMMARYThe heat denaturation of Fe-saturated lactoferrin (If) and Fe-free lactoferrin (apo-lf) was studied using the methods of micro-complement fixation and fluorescence. It was established that the change in conformation of apo-lf, induced by iron binding, conferred a higher heat stability to the molecule: the changes were observed at temperatures above 40 °C for apo-lf and above 60 °C for If. The Fe-binding ability of the protein was partially independent of the degree of denaturation. Fluorescence analyses indicated that tryptophan residues were probably not directly involved in the metal binding. There was no evidence of antibodies interfering with the binding sites.

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