SOME ASPECTS OF THE STRUCTURE OF HEMOGLOBIN

1964 ◽  
Vol 42 (6) ◽  
pp. 755-762 ◽  
Author(s):  
David B. Smith
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Partial Amino Acid Sequence ◽  
Heme Pocket ◽  
Terminal Amino ◽  
Polypeptide Chains ◽  
Kinetics Of ◽  
Β Chain

An outline of present ideas concerning the arrangement, folding, and chemistry of the polypeptide chains of hemoglobin is given with some references to present know ledge of myoglobin.New material includes a partial amino acid sequence of the β-chain of horse hemoglobin, details concerning the amino acids lining the heme pocket of horse hemoglobin, and the effects of carboxypeptidases A and B on horse oxy- and horse deoxy-hemoglobin. The kinetics of the latter reactions are not simple. The C-terminal amino acids are released more rapidly from the oxygenated form.

scholarly journals Amino Acid Sequence of a Feather Keratin From Silver Gull (Larus novae-hollandiae) and Comparison with One from Emu (Dromaius novae-hollandiae)

1974 ◽  
Vol 27 (4) ◽  
pp. 369 ◽  
Author(s):  
IJ O'Donnell ◽  
AS Inglis
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Tryptic Digestion ◽  
Crystalline Region ◽  
Feather Keratin ◽  
Matrix Region ◽  
Polypeptide Chains ◽  
Selection Of

The amino acid sequence of the major components of the silver gull feather calamus has been determined and compared with that of the emu. The sequenator was used with a modified Edman-Begg program to facilitate determination of the sequence of the large hydrophobic fragment obtained on tryptic digestion. The main features of the comparison were: (1) the overall structures of the polypeptide chains were similar, having non-crystalline cystine-rich sections towards either end of the chain separated by a large crystalline region of 62 residues which contained the majority of the hydrophobic and serine and glycine residues; (2) approximately one-sixth of the residues were different in the two species, with the majority of changes occurring in the tails (i.e. non-crystalline or matrix region). The data argue for stringent demands in the selection of amino acids for the crystalline part of the feather molecule, a severity that is probably comparable to the strict requirements for the sequence of some of the enzymes.

scholarly journals Type III Secretion of the Salmonella Effector Protein SopE Is Mediated via an N-Terminal Amino Acid Signal and Not an mRNA Sequence

2005 ◽  
Vol 187 (5) ◽  
pp. 1559-1567 ◽  
Author(s):  
M. H. Karavolos ◽  
M. Wilson ◽  
J. Henderson ◽  
J. J. Lee ◽  
C. M. A. Khan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Host Cell ◽  
Type Iii Secretion ◽  
Effector Protein ◽  
Mrna Sequence ◽  
Type Iii ◽  
Amino Terminal ◽  
Terminal Amino

ABSTRACT Type III secretion systems (TTSS) are virulence-associated components of many gram-negative bacteria that translocate bacterial proteins directly from the bacterial cytoplasm into the host cell. The Salmonella translocated effector protein SopE has no consensus cleavable amino-terminal secretion sequence, and the mechanism leading to its secretion through the Salmonella pathogenicity island 1 (SPI-1) TTSS is still not fully understood. There is evidence from other bacteria which suggests that the TTSS signal may reside within the 5′ untranslated region (UTR) of the mRNA of secreted effectors. We investigated the role of the 5′ UTR in the SPI-1 TTSS-mediated secretion of SopE using promoter fusions and obtained data indicating that the mRNA sequence is not involved in the secretion process. To clarify the proteinaceous versus RNA nature of the signal, we constructed frameshift mutations in the amino-terminal region of SopE of Salmonella enterica serovar Typhimurium SL1344. Only constructs with the native amino acid sequence were secreted, highlighting the importance of the amino acid sequence versus the mRNA sequence for secretion. Additionally, we obtained frameshift mutation data suggesting that the first 15 amino acids are important for secretion of SopE independent of the presence of the chaperone binding site. These data shed light on the nature of the signal for SopE secretion and highlight the importance of the amino-terminal amino acids for correct targeting and secretion of SopE via the SPI-1-encoded TTSS during host cell invasion.

The Croonian Lecture, 1966 - The genetic code

1967 ◽  
Vol 167 (1009) ◽  
pp. 331-347 ◽  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nucleic Acid ◽  
Amino Acid Sequence ◽  
Genetic Code ◽  
Polypeptide Chain ◽  
Amino Acid Residues ◽  
Standard Set ◽  
Polypeptide Chains

Genes are made of nucleic acid. Enzymes are made of protein. The amino acid sequence of a particular protein is synthesized under instruction from a particular piece of nucleic acid. Each protein is made of one or more polypeptide chains, synthesized by condensing together amino acids, head to tail, with the elimination of water. A typical polypeptide chain is several hundred amino acid residues long. Nevertheless only twenty different kinds of amino acids are commonly found in proteins. This standard set of twenty is the same throughout nature. Nucleic acid is made of polynucleotide chains. The repeating unit of the chain is a sugar (ribose for RNA , deoxyribose for DNA ) connected to a phosphate. A base is joined on to each sugar. There are four common bases in nucleic acid. DNA usually has adenine, guanine, cytosine and thymine. In RNA thymine is replaced by uracil.

Nucleotide sequence of complementary DNA and derived amino acid sequence of murine complement protein C3

1984 ◽  
Vol 306 (1129) ◽  
pp. 333-344 ◽  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Transition Region ◽  
Sequence Homology ◽  
Complement Protein ◽  
Single Chain ◽  
Complementary Dna ◽  
Α Chain ◽  
Β Chain

The nucleotide sequences coding for murine complement component C3 have been determined from a cloned genomic DNA fragment and several overlapping cloned complementary DNA fragments. The amino acid sequence of the protein was deduced. The mature β and α subunits contain 642 and 993 amino acids respectively. Including a 24 amino acid signal peptide and four arginines in the β—α transition region, which are probably not contained in the mature protein, the unglycosylated single chain precursor protein preproC3 would have a molecular mass of 186484 Da and consist of 1663 amino acid residues. The C3 messenger RNA would be composed of a 56 + 2 nucleotide long 5' non-translated region, 4992 nucleotides of coding sequence, and a 3' non-translated region of 39 nucleotides, excluding the poly A tail. The β chain contains only three cysteine residues, the α chain 24, ten of which are clustered in the carboxy terminal stretch of 175 amino acids. Two potential carbohydrate attachment sites are predicted for the α chain, none for the β chain. From a comparison with human C3 cDNA sequence (of which over 80% has been determined) an extensive overall sequence homology was observed. Human and murine preproC3 would be of very similar length and share several noteworthy properties: the same order of the subunits in the precursor, the same basic residue multiplet in the β-a transition region, and a glutamine residue in the thioester region. The equivalent position of the known factor I cleavage sites in human C3a could be located in the murine C3 α chain and the size and sequence of the resulting peptide were deduced. A comparison of the amino acid sequences of murine G3 and human alpha2-macroglobulin is given. Several areas of strong sequence homology are observed, and we conclude that the two genes must have evolved from a common ancestor.

Complete Covalent Structure of Human Platelet Factor 4

1979 ◽  
Vol 42 (05) ◽  
pp. 1652-1660 ◽  
Author(s):  
Francis J Morgan ◽  
Geoffrey S Begg ◽  
Colin N Chesterman
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Human Platelet ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
Disulphide Bonds ◽  
Covalent Structure

SummaryThe amino acid sequence of the subunit of human platelet factor 4 has been determined. Human platelet factor 4 consists of identical subunits containing 70 amino acids, each with a molecular weight of 7,756. The molecule contains no methionine, phenylalanine or tryptophan. The proposed amino acid sequence of PF4 is: Glu-Ala-Glu-Glu-Asp-Gly-Asp-Leu-Gln-Cys-Leu-Cys-Val-Lys-Thr-Thr-Ser- Gln-Val-Arg-Pro-Arg-His-Ile-Thr-Ser-Leu-Glu-Val-Ile-Lys-Ala-Gly-Pro-His-Cys-Pro-Thr-Ala-Gin- Leu-Ile-Ala-Thr-Leu-Lys-Asn-Gly-Arg-Lys-Ile-Cys-Leu-Asp-Leu-Gln-Ala-Pro-Leu-Tyr-Lys-Lys- Ile-Ile-Lys-Lys-Leu-Leu-Glu-Ser. From consideration of the homology with p-thromboglobulin, disulphide bonds between residues 10 and 36 and between residues 12 and 52 can be inferred.

C-Terminal amino acid sequence of chicken pepsinogen and its homology with sequences of other acid proteases

1980 ◽  
Vol 45 (4) ◽  
pp. 1144-1154 ◽  
Author(s):  
Miroslav Baudyš ◽  
Helena Keilová ◽  
Vladimír Kostka
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
The Other ◽  
Terminal Sequence ◽  
Terminal Part ◽  
Terminal Amino Acid ◽  
Tryptic Peptides ◽  
Terminal Amino ◽  
High Degree ◽  
Terminal Amino Acid Sequence

To determine the primary structure of the C-terminal part of the molecule of chicken pepsinogen the tryptic, chymotryptic and thermolytic digest of the protein were investigated and peptides derived from this region were sought. These peptides permitted the following 21-residue C-terminal sequence to be determined: ...Ile-Arg-Glu-Tyr-Tyr-Val-Ile-Phe-Asp-Arg-Ala-Asn-Asn-Lys-Val-Gly-Leu-Ser-Pro-Leu-Ser.COOH. A comparison of this structure with the C-terminal sequential regions of the other acid proteases shows a high degree of homology between chicken pepsinogen and these proteases (e.g., the degree of homology with respect to hog pepsinogen and calf prochymosin is about 66%). Additional tryptic peptides, derived from the N-terminal part of the zymogen molecule whose amino acid sequence has been reported before, were also obtained in this study. This sequence was extended by two residues using an overlapping peptide. An ancillary result of this study was the isolation of tryptic peptides derived from other regions of the zymogen molecule.

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