13 Papain, X-Ray Structure

Publisher Summary This chapter describes the three-dimensional structure of the papain molecule by X-ray crystal structure analysis. For an accurate structure determination by X-ray diffraction, single crystals with dimensions of 0.2–0.5 mm are required. The periodic repetition of the unit cells leads to a pattern of diffracted X-ray beams. From the diffraction directions, the symmetry in the pattern and the extinction of certain beams, the dimensions and the symmetry of the unit cell can be derived. To calculate the electron density in the unit cell, the intensities of the diffracted beams and their phase relationship are required. The interaction between enzyme and substrate occurs at the surface of the papain molecule in a groove that is situated between the two parts of the molecule. The side chain of Cys 25 is found in the groove. If the sulfhydryl (SH) group is not free but blocked by heavy atoms, by alkylating reagents or by disulfide formation, the activity disappears completely.

[1]  J. Drenth,et al.  The crystal structure of papain: II. A three-dimensional fourier synthesis at 4.5 Å resolution , 1967 .

[2]  M. Perutz,et al.  The structure of haemoglobin - IV. Sign determination by the isomorphous replacement method , 1954, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[3]  J. Drenth,et al.  Structure of Papain , 1968, Nature.

[4]  J. Drenth,et al.  The Unit Cell of Mercuripapain Crystals , 1959, Nature.

[5]  A. North,et al.  The combination of isomorphous replacement and anomalous scattering data in phase determination of non-centrosymmetric reflexions , 1965 .

[6]  J. Drenth,et al.  The crystal structure of papain C , 1962 .

[7]  R. Frater,et al.  CURRENT STATUS OF THE STRUCTURE OF PAPAIN: THE LINEAR SEQUENCE, ACTIVE SULFHYDRYL GROUP, AND THE DISULFIDE BRIDGES. , 1964, Proceedings of the National Academy of Sciences of the United States of America.

[8]  D. Phillips.  On the design of single crystal diffractometers to measure a number of reflections simultaneously , 1964 .

[9]  M. O. Dayhoff,et al.  Atlas of protein sequence and structure , 1965 .

[10]  W. Hol,et al.  Papain in water-rich and in methanol-rich media; crystallization and conformation. , 1968, Journal of Molecular Biology.

[11]  L. Sluyterman,et al.  The activity of papain in the crystalline state. , 1969, Biochimica et biophysica acta.

[12]  A. Stockell.  A new crystalline form of mercuripapain , 1961 .

[13]  B. Matthews.  The extension of the isomorphous replacement method to include anomalous scattering measurements , 1966 .

[14]  J. Bijvoet,et al.  The Fourier synthesis of the crystal structure of strychnine sulphate pentahydrate , 1951 .

[15]  B. Wolthers.  Kinetics of inhibition of papain by TLCK and TPCK in the presence of BAEE as substrate , 1969, FEBS Letters.

[16]  F. Schneider.  Kooperative Imidazol-SH-Katalyse als enzymatische Modellreaktion , 1967 .

[17]  L. Sluyterman.  The activation reaction of papain. , 1967, Biochimica et biophysica acta.

[18]  A. North,et al.  Adaptation of a linear diffractometer to measure three X-ray reflections quasi-simultaneously , 1964 .

[19]  U. Arndt,et al.  The linear diffractometer , 1961 .