Abstract
The consequences of site-directed mutagenesis experiments are often anticipated by empirical rules regarding the expected effects of a given amino acid substitution. Here, we examine the effects of "conservative" and "nonconservative" substitutions on the X-ray crystal structures of human recombinant FKBP12 mutants in complex with the immunosuppressant drug FK506 (tacrolimus). R42K and R42I mutant complexes show 110-fold and 180-fold decreased calcineurin (CN) inhibition, respectively, versus the native complex, yet retain full peptidyl prolyl isomerase (PPIase) activity, FK506 binding, and FK506-mediated PPIase inhibition. Interestingly, the structure of the R42I mutant complex is better conserved than that of the R42K mutant complex when compared to the native complex structure, within both the FKBP12 protein and FK506 ligand regions of the complexes, and with respect to temperature factors and RMS coordinate differences. This is due to compensatory interactions mediated by two newly ordered water molecules in the R42I complex structure, molecules that act as surrogates for the missing arginine guanidino nitrogens of R42. The absence of such surrogate solvent interactions in the R42K complex leads to some disorder in the so-called "40s loop" that encompasses the substituent. One rationalization proposed for the observed loss in CN inhibition in these R42 mutant complexes invokes indirect effects leading to a misorientation of FKBP12 and FK506 structural elements that normally interact with calcineurin. Our results with the structure of the R42I complex in particular suggest that the observed loss of CN inhibition might also be explained by the loss of a specific R42-mediated interaction with CN that cannot be mimicked effectively by the solvent molecules that otherwise stabilize the conformation of the 40s loop in that structure.
Full Text
The Full Text of this article is available as a PDF (6.7 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Alber T., Sun D. P., Wilson K., Wozniak J. A., Cook S. P., Matthews B. W. Contributions of hydrogen bonds of Thr 157 to the thermodynamic stability of phage T4 lysozyme. Nature. 1987 Nov 5;330(6143):41–46. doi: 10.1038/330041a0. [DOI] [PubMed] [Google Scholar]
- Aldape R. A., Futer O., DeCenzo M. T., Jarrett B. P., Murcko M. A., Livingston D. J. Charged surface residues of FKBP12 participate in formation of the FKBP12-FK506-calcineurin complex. J Biol Chem. 1992 Aug 15;267(23):16029–16032. [PubMed] [Google Scholar]
- Armistead D. M., Badia M. C., Deininger D. D., Duffy J. P., Saunders J. O., Tung R. D., Thomson J. A., DeCenzo M. T., Futer O., Livingston D. J. Design, synthesis and structure of non-macrocyclic inhibitors of FKBP12, the major binding protein for the immunosuppressant FK506. Acta Crystallogr D Biol Crystallogr. 1995 Jul 1;51(Pt 4):522–528. doi: 10.1107/S0907444994014502. [DOI] [PubMed] [Google Scholar]
- Becker J. W., Rotonda J., McKeever B. M., Chan H. K., Marcy A. I., Wiederrecht G., Hermes J. D., Springer J. P. FK-506-binding protein: three-dimensional structure of the complex with the antagonist L-685,818. J Biol Chem. 1993 May 25;268(15):11335–11339. [PubMed] [Google Scholar]
- Bernstein F. C., Koetzle T. F., Williams G. J., Meyer E. F., Jr, Brice M. D., Rodgers J. R., Kennard O., Shimanouchi T., Tasumi M. The Protein Data Bank: a computer-based archival file for macromolecular structures. J Mol Biol. 1977 May 25;112(3):535–542. doi: 10.1016/s0022-2836(77)80200-3. [DOI] [PubMed] [Google Scholar]
- Bierer B. E., Mattila P. S., Standaert R. F., Herzenberg L. A., Burakoff S. J., Crabtree G., Schreiber S. L. Two distinct signal transmission pathways in T lymphocytes are inhibited by complexes formed between an immunophilin and either FK506 or rapamycin. Proc Natl Acad Sci U S A. 1990 Dec;87(23):9231–9235. doi: 10.1073/pnas.87.23.9231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clardy J. Structural studies of complexed FK-506 binding protein. Ann N Y Acad Sci. 1993 Jun 23;685:37–45. doi: 10.1111/j.1749-6632.1993.tb35848.x. [DOI] [PubMed] [Google Scholar]
- Clardy J. The chemistry of signal transduction. Proc Natl Acad Sci U S A. 1995 Jan 3;92(1):56–61. doi: 10.1073/pnas.92.1.56. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Connelly P. R., Aldape R. A., Bruzzese F. J., Chambers S. P., Fitzgibbon M. J., Fleming M. A., Itoh S., Livingston D. J., Navia M. A., Thomson J. A. Enthalpy of hydrogen bond formation in a protein-ligand binding reaction. Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1964–1968. doi: 10.1073/pnas.91.5.1964. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dumont F. J., Staruch M. J., Koprak S. L., Melino M. R., Sigal N. H. Distinct mechanisms of suppression of murine T cell activation by the related macrolides FK-506 and rapamycin. J Immunol. 1990 Jan 1;144(1):251–258. [PubMed] [Google Scholar]
- Friedman J., Weissman I. Two cytoplasmic candidates for immunophilin action are revealed by affinity for a new cyclophilin: one in the presence and one in the absence of CsA. Cell. 1991 Aug 23;66(4):799–806. doi: 10.1016/0092-8674(91)90123-g. [DOI] [PubMed] [Google Scholar]
- Futer O., DeCenzo M. T., Aldape R. A., Livingston D. J. FK506 binding protein mutational analysis. Defining the surface residue contributions to stability of the calcineurin co-complex. J Biol Chem. 1995 Aug 11;270(32):18935–18940. doi: 10.1074/jbc.270.32.18935. [DOI] [PubMed] [Google Scholar]
- Griffith J. P., Kim J. L., Kim E. E., Sintchak M. D., Thomson J. A., Fitzgibbon M. J., Fleming M. A., Caron P. R., Hsiao K., Navia M. A. X-ray structure of calcineurin inhibited by the immunophilin-immunosuppressant FKBP12-FK506 complex. Cell. 1995 Aug 11;82(3):507–522. doi: 10.1016/0092-8674(95)90439-5. [DOI] [PubMed] [Google Scholar]
- Kino T., Hatanaka H., Hashimoto M., Nishiyama M., Goto T., Okuhara M., Kohsaka M., Aoki H., Imanaka H. FK-506, a novel immunosuppressant isolated from a Streptomyces. I. Fermentation, isolation, and physico-chemical and biological characteristics. J Antibiot (Tokyo) 1987 Sep;40(9):1249–1255. doi: 10.7164/antibiotics.40.1249. [DOI] [PubMed] [Google Scholar]
- Liu J., Farmer J. D., Jr, Lane W. S., Friedman J., Weissman I., Schreiber S. L. Calcineurin is a common target of cyclophilin-cyclosporin A and FKBP-FK506 complexes. Cell. 1991 Aug 23;66(4):807–815. doi: 10.1016/0092-8674(91)90124-h. [DOI] [PubMed] [Google Scholar]
- Matthews B. W. Structural and genetic analysis of protein stability. Annu Rev Biochem. 1993;62:139–160. doi: 10.1146/annurev.bi.62.070193.001035. [DOI] [PubMed] [Google Scholar]
- Park S. T., Aldape R. A., Futer O., DeCenzo M. T., Livingston D. J. PPIase catalysis by human FK506-binding protein proceeds through a conformational twist mechanism. J Biol Chem. 1992 Feb 15;267(5):3316–3324. [PubMed] [Google Scholar]
- Rotonda J., Burbaum J. J., Chan H. K., Marcy A. I., Becker J. W. Improved calcineurin inhibition by yeast FKBP12-drug complexes. Crystallographic and functional analysis. J Biol Chem. 1993 Apr 15;268(11):7607–7609. doi: 10.2210/pdb1yat/pdb. [DOI] [PubMed] [Google Scholar]
- Schreiber S. L. Chemistry and biology of the immunophilins and their immunosuppressive ligands. Science. 1991 Jan 18;251(4991):283–287. doi: 10.1126/science.1702904. [DOI] [PubMed] [Google Scholar]
- Sehgal S. N., Baker H., Vézina C. Rapamycin (AY-22,989), a new antifungal antibiotic. II. Fermentation, isolation and characterization. J Antibiot (Tokyo) 1975 Oct;28(10):727–732. doi: 10.7164/antibiotics.28.727. [DOI] [PubMed] [Google Scholar]
- Teague S. Lessons from molecular matchmakers. Nat Struct Biol. 1995 May;2(5):360–361. doi: 10.1038/nsb0595-360. [DOI] [PubMed] [Google Scholar]
- Van Duyne G. D., Standaert R. F., Karplus P. A., Schreiber S. L., Clardy J. Atomic structure of FKBP-FK506, an immunophilin-immunosuppressant complex. Science. 1991 May 10;252(5007):839–842. doi: 10.1126/science.1709302. [DOI] [PubMed] [Google Scholar]
- Van Duyne G. D., Standaert R. F., Karplus P. A., Schreiber S. L., Clardy J. Atomic structures of the human immunophilin FKBP-12 complexes with FK506 and rapamycin. J Mol Biol. 1993 Jan 5;229(1):105–124. doi: 10.1006/jmbi.1993.1012. [DOI] [PubMed] [Google Scholar]
- Wilson K. P., Yamashita M. M., Sintchak M. D., Rotstein S. H., Murcko M. A., Boger J., Thomson J. A., Fitzgibbon M. J., Black J. R., Navia M. A. Comparative X-ray structures of the major binding protein for the immunosuppressant FK506 (tacrolimus) in unliganded form and in complex with FK506 and rapamycin. Acta Crystallogr D Biol Crystallogr. 1995 Jul 1;51(Pt 4):511–521. doi: 10.1107/S0907444994014514. [DOI] [PubMed] [Google Scholar]