title: Ribonuclease A suggests how proteins self-chaperone against amyloid fiber formation.
abstract: Genomic analyses have identified segments with high fiber-forming propensity in many proteins not known to form amyloid. Proteins are often protected from entering the amyloid state by molecular chaperones that permit them to fold in isolation from identical molecules; but, how do proteins self-chaperone their folding in the absence of chaperones? Here, we explore this question with the stable protein ribonuclease A (RNase A). We previously identified fiber-forming segments of amyloid-related proteins and demonstrated that insertion of these segments into the C-terminal hinge loop of nonfiber-forming RNase A can convert RNase A into the amyloid state through three-dimensional domain-swapping, where the inserted fiber-forming segments interact to create a steric zipper spine. In this study, we convert RNase A into amyloid-like fibers by increasing the loop length and hence conformational freedom of an endogenous fiber-forming segment, SSTSAASS, in the N-terminal hinge loop. This is accomplished by sandwiching SSTSAASS between inserted Gly residues. With these inserts, SSTSAASS is now able to form the steric zipper spine, allowing RNase A to form amyloid-like fibers. We show that these fibers contain RNase A molecules retaining their enzymatic activity and therefore native-like structure. Thus, RNase A appears to prevent fiber formation by limiting the conformational freedom of this fiber-forming segment from entering a steric zipper. Our observations suggest that proteins have evolved to self-chaperone by using similar protective mechanisms.
authors.affiliation: Departments of Chemistry & Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California-Los Angeles, 611 Charles Young Drive East, CA 90095-1570, USA.
authors.forename: Poh K
authors.initials: PK
authors.lastname: Teng
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Anderson
authors.forename: Lukasz
authors.initials: L
authors.lastname: Goldschmidt
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sawaya
authors.forename: Shilpa
authors.initials: S
authors.lastname: Sambashivan
authors.forename: David
authors.initials: D
authors.lastname: Eisenberg
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000682:Amyloid; D012259:Ribonuclease, Pancreatic
references.citation: J Biol Chem. 1959 Jun;234(6):1459-65
references.pmid: 13654398
references.citation: Bioorg Chem. 1995 Dec;23(4):471-481
references.pmid: 21799547
references.citation: Nature. 2005 Sep 8;437(7056):266-9
references.pmid: 16148936
references.citation: Biochemistry. 1988 Apr 19;27(8):2705-17
references.pmid: 3401445
references.citation: Proc Natl Acad Sci U S A. 1984 Dec;81(24):7674-8
references.pmid: 6595655
references.citation: Proc Natl Acad Sci U S A. 2010 Feb 23;107(8):3487-92
references.pmid: 20133726
references.citation: Nature. 1967 Mar 4;213(5079):862-5
references.pmid: 6043657
references.citation: Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15463-8
references.pmid: 14665689
references.citation: Biopolymers. 2008;90(3):278-86
references.pmid: 17610259
references.citation: Proc Natl Acad Sci U S A. 1998 Mar 31;95(7):3437-42
references.pmid: 9520384
references.citation: J Histochem Cytochem. 1972 Oct;20(10):821-6
references.pmid: 4638557
references.citation: Proc Natl Acad Sci U S A. 2010 May 11;107(19):8633-8
references.pmid: 20421488
references.citation: J Biol Chem. 1967 Sep 10;242(17):3984-8
references.pmid: 6037556
references.citation: J Mol Biol. 1968 Mar 14;32(2):343-58
references.pmid: 5643439
references.citation: Science. 1957 Apr 12;125(3250):691-2
references.pmid: 13421663
references.citation: Biochemistry. 2004 Jun 22;43(24):7808-15
references.pmid: 15196023
references.citation: Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):905-21
references.pmid: 9757107
references.citation: Nature. 2007 May 24;447(7143):453-7
references.pmid: 17468747
references.citation: Proc Natl Acad Sci U S A. 2000 May 23;97(11):5750-5
references.pmid: 10811890
references.citation: Nature. 2005 Jun 9;435(7043):773-8
references.pmid: 15944695
references.citation: Biochim Biophys Acta. 2006 Jan;1764(1):44-54
references.pmid: 16310422
references.citation: J Mol Biol. 1993 Feb 5;229(3):722-34
references.pmid: 8381876
references.citation: Nat Struct Mol Biol. 2011 Jan;18(1):49-55
references.pmid: 21131979
references.citation: Biochim Biophys Acta. 2001 Feb 9;1545(1-2):255-62
references.pmid: 11342051
references.citation: Protein Sci. 2000 Oct;9(10):2026-33
references.pmid: 11106177
references.citation: Biochemistry. 1967 Jan;6(1):304-12
references.pmid: 6030327
references.citation: Trends Biochem Sci. 1999 Sep;24(9):329-32
references.pmid: 10470028
references.citation: Biochim Biophys Acta. 2008 Apr;1784(4):638-50
references.pmid: 18261475
references.citation: J Histochem Cytochem. 1989 Aug;37(8):1273-81
references.pmid: 2666510
references.citation: Proteins. 2005 Nov 15;61(3):570-8
references.pmid: 16170782
references.citation: Acta Crystallogr A. 1991 Mar 1;47 ( Pt 2):110-9
references.pmid: 2025413
references.citation: Nat Struct Biol. 2001 Mar;8(3):211-4
references.pmid: 11224563
references.citation: PLoS Biol. 2008 Aug 5;6(8):e195
references.pmid: 18684013
references.citation: Biochem J. 2004 Jun 1;380(Pt 2):311-27
references.pmid: 15104538
references.citation: Biochemistry. 1994 Jun 14;33(23):7408-14
references.pmid: 8003506
references.citation: Proc Natl Acad Sci U S A. 2006 Mar 14;103(11):4079-82
references.pmid: 16537488
references.citation: Biopolymers. 2008;90(3):259-77
references.pmid: 17868092
references.citation: Protein Eng Des Sel. 2009 Aug;22(8):531-6
references.pmid: 19602569
references.citation: Arch Biochem Biophys. 1962 Sep;Suppl 1:217-22
references.pmid: 14023810
references.citation: Proc Natl Acad Sci U S A. 2006 Mar 14;103(11):4074-8
references.pmid: 16537487
references.citation: Protein Sci. 1996 Oct;5(10):2104-14
references.pmid: 8897611
references.citation: Fold Des. 1997;2(1):R1-11
references.pmid: 9080194
references.citation: Cell. 2005 Apr 8;121(1):73-85
references.pmid: 15820680
references.citation: J Mol Biol. 2006 Sep 22;362(3):459-78
references.pmid: 16920150
references.citation: Adv Protein Chem. 1997;50:123-59
references.pmid: 9338080
references.citation: Biochemistry. 1992 Mar 10;31(9):2469-81
references.pmid: 1547232
references.citation: Biochem J. 1935 Oct;29(10):2351-2360.1
references.pmid: 16745914
references.citation: Proc Natl Acad Sci U S A. 2006 May 23;103(21):8042-7
references.pmid: 16698921
references.citation: Protein Sci. 2002 Feb;11(2):371-80
references.pmid: 11790847
references.citation: J Biol Chem. 2003 Mar 21;278(12):10763-9
references.pmid: 12533538
references.citation: Science. 1996 Aug 2;273(5275):622-6
references.pmid: 8662547
references.citation: Nat Struct Biol. 2001 Sep;8(9):770-4
references.pmid: 11524679
references.citation: Amyloid. 2007 Sep;14(3):179-83
references.pmid: 17701465
references.citation: Cold Spring Harb Symp Quant Biol. 1996;61:541-50
references.pmid: 9246480
references.citation: Cell. 2003 Dec 26;115(7):879-91
references.pmid: 14697205