Secondary structure of the cecropins: antibacterial peptides from the moth <i>Hyalophora cecropia</i>

Steiner, Håkan

doi:10.1016/0014-5793(82)80368-2

Cited by 117 publications

(65 citation statements)

References 13 publications

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“…As the primary structure of the antibacterial proteins cannot offer an explanation for the InA specificity it has to be found in structures of higher order. In fact, it has been shown by circular dichroism measurements that the cecropins are largely in a random coil conformation in buffer solution [24]. Also attacins may have an open structure since they lack disulfide bridges [4].…”

Section: Discussionmentioning

confidence: 99%

Characterization of inhibitor A, a protease from Bacillus thuringiensis which degrades attacins and cecropins, two classes of antibacterial proteins in insects

1984

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The insect pathogen Bacillus thuringiensis produces an exoprotease, inhibitor A, at the beginning of the stationary growth phase. In vitro, the enzyme selectively destroys cecropins and attacins, two antibacterial proteins found in immune hemolymph from Hyalophora cecropia. The specificity of this enzyme was investigated using cecropin A(l-33) and HPLC for separation and characterization of the fragments obtained.A maximum of 12 different peptides were produced and their positions in the known sequence of cecropin A(1-33) were deduced from their amino acid compositions. The enzyme did not show a stringent requirement for a specific amino acid sequence at the cleavage site but prefers a hydrophobic residue on the C-terminal side. The specificity of the enzyme is explained in terms of the open structure of the cecropins and a pronounced inability of inhibitor A to attack globular proteins. It is generally accepted that the main insecticidal principle of the bacterium Bacillus thuringiensis resides in the proteinaceous crystal that is produced concomitantly with spore formation [8]. Compared to other bacteria B. thuringiensis is highly resistent to both cellular and humoral components of the immune system in insects. It has earlier been shown that B. thuringiensis produces two factors, inhibitor A (InA) and inhibitor B which selectively block the humoral defence system against. Escherichia coli and Bacillus cereus, respectively [9]. These extracellular factors were first found in a crystal negative mutant, Bt7. Inhibitor A was purified from the N-methyl-N'-nitro-N-nitrosoguanidine

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Section: Discussionmentioning

confidence: 99%

Characterization of inhibitor A, a protease from Bacillus thuringiensis which degrades attacins and cecropins, two classes of antibacterial proteins in insects

1984

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“…Considering their relatively small size it implies that they are devoid of 'genetic garbage'. The secondary structure of cecropins A and B have been studied earlier [14] and [14a]. The two proteins were predicted to have a strong potential for an amphipatic helix in their N-terminal part.…”

Section: Discussionmentioning

confidence: 99%

“…The conclusion must be that cecropin D has a potential for existing largely in a helical conformation with short connecting bends around residues 22 and maybe 13. From circular dichroism measurements such a high content of helix was calculated to exist in the A and B forms in a hydrophobic solvent [14]. A similar conformation may also be adopted upon contact with the bacterial target membrane.…”

Section: Discussionmentioning

confidence: 99%

Insect Immunity: Isolation and Structure of Cecropins B and D from Pupae of the Chinese Oak Silk Moth, Antheraea pernyi

Qu¹,

Steiner²,

Engström³

et al. 1982

Eur J Biochem

108

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The immune system in the Chinese oak silk moth, Antheraea pernyi, has been compared with that of the Cecropia moth which has been characterized earlier. Antibacterial activity against Escherichia coli was induced in diapausing pupae by injection of viable E. coli or Enterobacter cloacae. The activity reached a maximtlm on day 7 -8 after which the response gradually declined. The pupae produced a set of immune proteins with 1' 4 and P5 as major labelled components similar to that earlier found in Cecropia. The major antibacterial factor in A . pernyi was cecropin D.A procedure is described for the isolation of cecropin B and D, which is in principle similar to the one used for the isolation of the corresponding cecropins from Cecropia pupae. Amino acid sequence analyses of the A . pernyi cecropins show the D form to contain 36 amino acid residues and that both cecropins have blocked C-termini. The general structure of cecropins having a charged N-terminal region (residues 1-21) followed by a long hydrophobic stretch (residues 22 -32) is well conserved. Cecropin B and D from A . pernyi differ from the corresponding proteins in Cecropia by four and three conservative amino acid replacements, respectively. The homology between the cecropins from the two insects suggests that they orginate from a single ancestral gene. The antibacterial activity was tested against nine different bacterial species. Evolutionary aspects of the cecropins are discussed.

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“…cecropia [2]. Circular dichroism measurements were per- formed on a Carry 60 spectropolarimeter as described earlier [23]. The helical content was estimated from the mean residue ellipticity at 222 nm [24].…”

Section: Circular Dichroism Measurementsmentioning

confidence: 99%

Structure of preproattacin and its processing in insect cells infected with a recombinant baculovirus

Gunne¹,

Hellers²,

Steiner³

1990

European Journal of Biochemistry

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From a cDNA library made from fatbody of immunized Hyalophora cecropia pupae, a full-length clone corresponding to basic attacin was isolated. The corresponding amino acid sequence suggests that basic attacin is synthesized as a 233-residue preproprotein. This was confirmed by cloning the cDNA fragment encoding the basic attacin in the baculovirus Autographa californica nuclear polyhedrosis virus downstream of the polyhedrin promoter and expressing the protein in Spodoptera frug@erda (Sf9) cells. Biologically active attacin was also produced in last instar larvae of Trichoplusia ni after injection of recombinant virus. The concentration obtained was 300 ~ SO0 times that obtained in cell culture supernatants. In cell culture the induction kinetics of attacin were followed at both transcriptional and translational levels. From the protein processing pattern it was suggested that a protease produced by the Spodoptera cells cleaves attacin at the double arginine residues at positions 45 and 46. The instability of the attacin proteins is rationalized in terms of their random-coil structure which was deduced from circular dichroism measurements.

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Secondary structure of the cecropins: antibacterial peptides from the moth Hyalophora cecropia

Cited by 117 publications

References 13 publications

Characterization of inhibitor A, a protease from Bacillus thuringiensis which degrades attacins and cecropins, two classes of antibacterial proteins in insects

Characterization of inhibitor A, a protease from Bacillus thuringiensis which degrades attacins and cecropins, two classes of antibacterial proteins in insects

Insect Immunity: Isolation and Structure of Cecropins B and D from Pupae of the Chinese Oak Silk Moth, Antheraea pernyi

Structure of preproattacin and its processing in insect cells infected with a recombinant baculovirus

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