Self-assembly of spider silk proteins is controlled by a pH-sensitive relay

被引:359
作者
Askarieh, Glareh [1 ,2 ]
Hedhammar, My [3 ]
Nordling, Kerstin [3 ]
Saenz, Alejandra [4 ,5 ]
Casals, Cristina [4 ,5 ]
Rising, Anna [3 ]
Johansson, Jan [3 ]
Knight, Stefan D. [1 ]
机构
[1] SLU, Biomed Ctr, Uppsala BioCtr, Dept Mol Biol, SE-75124 Uppsala, Sweden
[2] Univ Oslo, Dept Chem, N-0315 Oslo, Norway
[3] SLU, Biomed Ctr, Dept Anat Physiol & Biochem, SE-75123 Uppsala, Sweden
[4] Univ Complutense Madrid, Dept Biochem & Mol Biol 1, E-28040 Madrid, Spain
[5] Univ Complutense Madrid, CIBER Enfermedades Resp, E-28040 Madrid, Spain
基金
瑞典研究理事会;
关键词
DRAGLINE; FIBROIN; DOMAIN; PHENIX;
D O I
10.1038/nature08962
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Nature's high-performance polymer, spider silk, consists of specific proteins, spidroins, with repetitive segments flanked by conserved non-repetitive domains(1,2). Spidroins are stored as a highly concentrated fluid dope. On silk formation, intermolecular interactions between repeat regions are established that provide strength and elasticity(3,4). How spiders manage to avoid premature spidroin aggregation before self-assembly is not yet established. A pH drop to 6.3 along the spider's spinning apparatus, altered salt composition and shear forces are believed to trigger the conversion to solid silk, but no molecular details are known. Miniature spidroins consisting of a few repetitive spidroin segments capped by the carboxy-terminal domain form metre-long silk-like fibres irrespective of pH(5). We discovered that incorporation of the amino-terminal domain of major ampullate spidroin 1 from the dragline of the nursery web spider Euprosthenops australis (NT) into mini-spidroins enables immediate, charge-dependent self-assembly at pH values around 6.3, but delays aggregation above pH7. The X-ray structure of NT, determined to 1.7 angstrom resolution, shows a homodimer of dipolar, antiparallel five-helix bundle subunits that lack homologues. The overall dimeric structure and observed charge distribution of NT is expected to be conserved through spider evolution and in all types of spidroins. Our results indicate a relay-like mechanism through which the N-terminal domain regulates spidroin assembly by inhibiting precocious aggregation during storage, and accelerating and directing self-assembly as the pH is lowered along the spider's silk extrusion duct.
引用
收藏
页码:236 / U125
页数:4
相关论文
共 27 条
[1]   PHENIX:: building new software for automated crystallographic structure determination [J].
Adams, PD ;
Grosse-Kunstleve, RW ;
Hung, LW ;
Ioerger, TR ;
McCoy, AJ ;
Moriarty, NW ;
Read, RJ ;
Sacchettini, JC ;
Sauter, NK ;
Terwilliger, TC .
ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY, 2002, 58 :1948-1954
[2]   Blueprint for a High-Performance Biomaterial: Full-Length Spider Dragline Silk Genes [J].
Ayoub, Nadia A. ;
Garb, Jessica E. ;
Tinghitella, Robin M. ;
Collin, Matthew A. ;
Hayashi, Cheryl Y. .
PLOS ONE, 2007, 2 (06)
[3]   THE CCP4 SUITE - PROGRAMS FOR PROTEIN CRYSTALLOGRAPHY [J].
BAILEY, S .
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY, 1994, 50 :760-763
[4]   A SPIDER FIBROIN AND ITS SYNTHESIS [J].
CANDELAS, GC ;
CINTRON, J .
JOURNAL OF EXPERIMENTAL ZOOLOGY, 1981, 216 (01) :1-6
[5]   Coot:: model-building tools for molecular graphics [J].
Emsley, P ;
Cowtan, K .
ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY, 2004, 60 :2126-2132
[6]  
Evans W, 1997, CHEM BRIT, V33, P22
[7]   STRANGE BEDFELLOWS - INTERACTIONS BETWEEN ACIDIC SIDE-CHAINS IN PROTEINS [J].
FLOCCO, MW ;
MOWBRAY, SL .
JOURNAL OF MOLECULAR BIOLOGY, 1995, 254 (01) :96-105
[8]   H++:: a server for estimating pKas and adding missing hydrogens to macromolecules [J].
Gordon, JC ;
Myers, JB ;
Folta, T ;
Shoja, V ;
Heath, LS ;
Onufriev, A .
NUCLEIC ACIDS RESEARCH, 2005, 33 :W368-W371
[9]  
Gosline JM, 1999, J EXP BIOL, V202, P3295
[10]   Structural properties of recombinant nonrepetitive and repetitive parts of major ampullate spidroin 1 from Euprosthenops australis:: Implications for fiber formation [J].
Hedhammar, My ;
Rising, Anna ;
Grip, Stefan ;
Martinez, Alejandra Saenz ;
Nordling, Kerstin ;
Casals, Cristina ;
Stark, Margareta ;
Johansson, Jan .
BIOCHEMISTRY, 2008, 47 (11) :3407-3417