PDBsum entry 2m0m

Protein fibril

PDB id: 2m0m

Contents

Protein chains

107 a.a.

PDB id:

2m0m

Name:

Protein fibril

Title:

Structural characterization of minor ampullate spidroin domains and their distinct roles in fibroin solubility and fiber formation

Structure:

Minor ampullate fibroin 1. Chain: a, b. Fragment: unp residues 250-356. Engineered: yes

Source:

Nephila antipodiana. Organism_taxid: 171624. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

10 models

Authors:

D.Yang,Z.Gao,Z.Lin,W.Huang,C.Lai,J.Fan

Key ref:

Z.Gao et al. (2013). Structural characterization of minor ampullate spidroin domains and their distinct roles in fibroin solubility and fiber formation. PLoS One, 8, e56142. PubMed id: 23418525

Date:

30-Oct-12 Release date: 27-Mar-13

Protein chains

Q2LC34  (Q2LC34_9ARAC) -  Minor ampullate fibroin 1 (Fragment) from Trichonephila antipodiana

Seq: 356 a.a.

Struc: 107 a.a.

Enzyme reactions

• Enzyme class: E.C.?

PLoS One 8:e56142 (2013)

PubMed id: 23418525

Structural characterization of minor ampullate spidroin domains and their distinct roles in fibroin solubility and fiber formation.

Z.Gao, Z.Lin, W.Huang, C.C.Lai, J.S.Fan, D.Yang.

ABSTRACT

Spider silk is protein fibers with extraordinary mechanical properties. Up to now, it is still poorly understood how silk proteins are kept in a soluble form before spinning into fibers and how the protein molecules are aligned orderly to form fibers. Minor ampullate spidroin is one of the seven types of silk proteins, which consists of four types of domains: N-terminal domain, C-terminal domain (CTD), repetitive domain (RP) and linker domain (LK). Here we report the tertiary structure of CTD and secondary structures of RP and LK in aqueous solution, and their roles in protein stability, solubility and fiber formation. The stability and solubility of individual domains are dramatically different and can be explained by their distinct structures. For the tri-domain miniature fibroin, RP-LK-CTD(Mi), the three domains have no or weak interactions with one another at low protein concentrations (<1 mg/ml). The CTD in RP-LK-CTD(Mi) is very stable and soluble, but it cannot stabilize the entire protein against chemical and thermal denaturation while it can keep the entire tri-domain in a highly water-soluble state. In the presence of shear force, protein aggregation is greatly accelerated and the aggregation rate is determined by the stability of folded domains and solubility of the disordered domains. Only the tri-domain RP-LK-CTD(Mi) could form silk-like fibers, indicating that all three domains play distinct roles in fiber formation: LK as a nucleation site for assembly of protein molecules, RP for assistance of the assembly and CTD for regulating alignment of the assembled molecules.