Skip to main content

Some NLM-NCBI services and products are experiencing heavy traffic, which may affect performance and availability. We apologize for the inconvenience and appreciate your patience. For assistance, please contact our Help Desk at info@ncbi.nlm.nih.gov.

The EMBO Journal logoLink to The EMBO Journal
. 1987 Jun;6(6):1565–1570. doi: 10.1002/j.1460-2075.1987.tb02401.x

The molecular structure of insecticyanin from the tobacco hornworm Manduca sexta L. at 2.6 A resolution.

H M Holden, W R Rypniewski, J H Law, I Rayment
PMCID: PMC553525  PMID: 3608987

Abstract

Insecticyanin, a blue biliprotein isolated from the tobacco hornworm Manduca sexta L., is involved in insect camouflage. Its three-dimensional structure has now been solved to 2.6 A resolution using the techniques of multiple isomorphous replacement, non-crystallographic symmetry averaging about a local 2-fold rotation axis and solvent flattening. All 189 amino acids have been fitted to the electron density map. The map clearly shows that insecticyanin is a tetramer with one of its molecular 2-fold axes coincident to a crystallographic dyad. The individual subunits have overall dimensions of 44 A X 37 A X 40 A and consist primarily of an eight-stranded anti-parallel beta-barrel flanked on one side by a 4.5-turn alpha-helix. Interestingly the overall three-dimensional fold of the insecticyanin subunit shows remarkable similarity to the structural motifs of bovine beta-lactoglobulin and the human serum retinol-binding protein. The electron density attributable to the chromophore is unambiguous and shows that it is indeed the gamma-isomer of biliverdin. The biliverdin lies towards the open end of the beta-barrel with its two propionate side chains pointing towards the solvent and it adopts a rather folded conformation, much like a heme.

Full text

PDF
1565

Images in this article

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Goodman W. G., Adams B., Trost J. T. Purification and characterization of a biliverdin-associated protein from the hemolymph of Manduca sexta. Biochemistry. 1985 Feb 26;24(5):1168–1175. doi: 10.1021/bi00326a017. [DOI] [PubMed] [Google Scholar]
  2. Holden H. M., Law J. H., Rayment I. Crystallization of insecticyanin from the hemolymph of the tobacco hornworm Manduca sexta L. in a form suitable for a high resolution structure determination. J Biol Chem. 1986 Mar 25;261(9):4217–4218. [PubMed] [Google Scholar]
  3. Jones T. A. Diffraction methods for biological macromolecules. Interactive computer graphics: FRODO. Methods Enzymol. 1985;115:157–171. doi: 10.1016/0076-6879(85)15014-7. [DOI] [PubMed] [Google Scholar]
  4. KRAUT J., SIEKER L. C., HIGH D. F., FREER S. T. Chymotrypsinogen: a three-dimensional fourier synthesis at 5 angstrom resolution. Proc Natl Acad Sci U S A. 1962 Aug;48:1417–1424. doi: 10.1073/pnas.48.8.1417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Newcomer M. E., Jones T. A., Aqvist J., Sundelin J., Eriksson U., Rask L., Peterson P. A. The three-dimensional structure of retinol-binding protein. EMBO J. 1984 Jul;3(7):1451–1454. doi: 10.1002/j.1460-2075.1984.tb01995.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Papiz M. Z., Sawyer L., Eliopoulos E. E., North A. C., Findlay J. B., Sivaprasadarao R., Jones T. A., Newcomer M. E., Kraulis P. J. The structure of beta-lactoglobulin and its similarity to plasma retinol-binding protein. 1986 Nov 27-Dec 3Nature. 324(6095):383–385. doi: 10.1038/324383a0. [DOI] [PubMed] [Google Scholar]
  7. Riddiford L. M. Changes in translatable mRNAs during the larval-pupal transformation of the epidermis of the tobacco hornworm. Dev Biol. 1982 Aug;92(2):330–342. doi: 10.1016/0012-1606(82)90179-8. [DOI] [PubMed] [Google Scholar]
  8. Riley C. T., Barbeau B. K., Keim P. S., Kézdy F. J., Heinrikson R. L., Law J. H. The covalent protein structure of insecticyanin, a blue biliprotein from the hemolymph of the tobacco hornworm, Manduca sexta L. J Biol Chem. 1984 Nov 10;259(21):13159–13165. [PubMed] [Google Scholar]
  9. Schirmer T., Bode W., Huber R., Sidler W., Zuber H. X-ray crystallographic structure of the light-harvesting biliprotein C-phycocyanin from the thermophilic cyanobacterium Mastigocladus laminosus and its resemblance to globin structures. J Mol Biol. 1985 Jul 20;184(2):257–277. doi: 10.1016/0022-2836(85)90379-1. [DOI] [PubMed] [Google Scholar]
  10. Schirmer T., Huber R., Schneider M., Bode W., Miller M., Hackert M. L. Crystal structure analysis and refinement at 2.5 A of hexameric C-phycocyanin from the cyanobacterium Agmenellum quadruplicatum. The molecular model and its implications for light-harvesting. J Mol Biol. 1986 Apr 20;188(4):651–676. doi: 10.1016/s0022-2836(86)80013-4. [DOI] [PubMed] [Google Scholar]

Articles from The EMBO Journal are provided here courtesy of Nature Publishing Group

RESOURCES