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. 1982 Mar 1;92(3):742–746. doi: 10.1083/jcb.92.3.742

Chemical modification of matrix porin from Escherichia coli: probing the pore topology of a transmembrane protein

PMCID: PMC2112050  PMID: 6177703

Abstract

Chemical modification of amino groups in matrix porin solubilized and purified from outer membranes of Escherichia coli in beta- octylglucoside was performed with eosin isothiocyanate and citraconic anhydride. At pH 7 8.5, the former reagent labeled a single amino group in the native protein, while more extensive derivatization was observed with increasing pH or upon denaturation. Citraconic anhydride modified approximately 12-14 residues in native porin and 15-16 of the total of 19 amino groups in the denatured state. Fluorescamine, another amine- specific reagent of intermediate size, derivatized 3 and 16 residues in the native and denatured states, respectively. These results indicate that reactive probes of various sizes may serve as indicators for the surface accessibility of reactive residues in matrix porin. The increased derivatization of lysyl residues at high pH (or in phosphate buffer) suggests the method's sensitivity to different conformational states of the protein. The extent of tyrosine modification (1-2 residues in the native, and approximately 22 in the denatured porin) depended on the state of protein folding, even with reagents of small size. The approach of using various probes with differing properties and specificities thus appears useful for the determination of membrane protein asymmetry, pore topology, and conformational states of transmembrane proteins.

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Selected References

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  1. Benz R., Janko K., Boos W., Läuger P. Formation of large, ion-permeable membrane channels by the matrix protein (porin) of Escherichia coli. Biochim Biophys Acta. 1978 Aug 17;511(3):305–319. doi: 10.1016/0005-2736(78)90269-9. [DOI] [PubMed] [Google Scholar]
  2. Boesel R. W., Carpenter F. H. Crosslinking during the nitration of bovine insulin with tetranitromethane. Biochem Biophys Res Commun. 1970 Feb 20;38(4):678–682. doi: 10.1016/0006-291x(70)90634-0. [DOI] [PubMed] [Google Scholar]
  3. Cabantchik Z. I., Knauf P. A., Rothstein A. The anion transport system of the red blood cell. The role of membrane protein evaluated by the use of 'probes'. Biochim Biophys Acta. 1978 Sep 29;515(3):239–302. doi: 10.1016/0304-4157(78)90016-3. [DOI] [PubMed] [Google Scholar]
  4. Chen R., Krämer C., Schmidmayr W., Henning U. Primary structure of major outer membrane protein I of Escherichia coli B/r. Proc Natl Acad Sci U S A. 1979 Oct;76(10):5014–5017. doi: 10.1073/pnas.76.10.5014. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Cherry R. J. Measurement of protein rotational diffusion in membranes by flash photolysis. Methods Enzymol. 1978;54:47–61. doi: 10.1016/s0076-6879(78)54007-x. [DOI] [PubMed] [Google Scholar]
  6. Engelman D. M., Henderson R., McLachlan A. D., Wallace B. A. Path of the polypeptide in bacteriorhodopsin. Proc Natl Acad Sci U S A. 1980 Apr;77(4):2023–2027. doi: 10.1073/pnas.77.4.2023. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Garavito R. M., Rosenbusch J. P. Three-dimensional crystals of an integral membrane protein: an initial x-ray analysis. J Cell Biol. 1980 Jul;86(1):327–329. doi: 10.1083/jcb.86.1.327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Ichihara S., Mizushima S. Arrangement of proteins O-8 and O-9 in outer membrane of Escherichia coli K-12. Existence of homotrimers and heterotrimers. Eur J Biochem. 1979 Oct 15;100(2):321–328. doi: 10.1111/j.1432-1033.1979.tb04174.x. [DOI] [PubMed] [Google Scholar]
  9. Kamio Y., Nikaido H. Outer membrane of Salmonella typhimurium. Identification of proteins exposed on cell surface. Biochim Biophys Acta. 1977 Feb 4;464(3):589–601. doi: 10.1016/0005-2736(77)90033-5. [DOI] [PubMed] [Google Scholar]
  10. Nikaido H., Nakae T. The outer membrane of Gram-negative bacteria. Adv Microb Physiol. 1979;20:163–250. doi: 10.1016/s0065-2911(08)60208-8. [DOI] [PubMed] [Google Scholar]
  11. Palva E. T., Randall L. L. Arrangement of protein I in Escherichia coli outer membrane: cross-linking study. J Bacteriol. 1978 Jan;133(1):279–286. doi: 10.1128/jb.133.1.279-286.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Palva E. T., Randall L. L. Nearest-neighbor analysis of Escherichia coli outer membrane proteins using cleavable cross-links. J Bacteriol. 1976 Sep;127(3):1558–1560. doi: 10.1128/jb.127.3.1558-1560.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Reithmeier R. A., Bragg P. D. Cross-linking of the proteins in the outer membrane of Escherichia coli. Biochim Biophys Acta. 1977 Apr 18;466(2):245–256. doi: 10.1016/0005-2736(77)90222-x. [DOI] [PubMed] [Google Scholar]
  14. Riordan J. F., Sokolovsky M., Vallee B. L. Environmentally sensitive tyrosyl residues. Nitration with tetranitromethane. Biochemistry. 1967 Jan;6(1):358–361. doi: 10.1021/bi00853a053. [DOI] [PubMed] [Google Scholar]
  15. Rosenbusch J. P. Characterization of the major envelope protein from Escherichia coli. Regular arrangement on the peptidoglycan and unusual dodecyl sulfate binding. J Biol Chem. 1974 Dec 25;249(24):8019–8029. [PubMed] [Google Scholar]
  16. Schindler H., Rosenbusch J. P. Matrix protein from Escherichia coli outer membranes forms voltage-controlled channels in lipid bilayers. Proc Natl Acad Sci U S A. 1978 Aug;75(8):3751–3755. doi: 10.1073/pnas.75.8.3751. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Schindler H., Rosenbusch J. P. Matrix protein in planar membranes: clusters of channels in a native environment and their functional reassembly. Proc Natl Acad Sci U S A. 1981 Apr;78(4):2302–2306. doi: 10.1073/pnas.78.4.2302. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Steven A. C., Heggeler B., Müller R., Kistler J., Rosenbusch J. P. Ultrastructure of a periodic protein layer in the outer membrane of Escherichia coli. J Cell Biol. 1977 Feb;72(2):292–301. doi: 10.1083/jcb.72.2.292. [DOI] [PMC free article] [PubMed] [Google Scholar]

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