Tags

Type your tag names separated by a space and hit enter

Spider egg case core fibers: trimeric complexes assembled from TuSp1, ECP-1, and ECP-2.
Biochemistry 2006; 45(11):3506-16B

Abstract

Spider silk proteins are well-known for their extraordinary mechanical properties, displaying remarkable strength and toughness. In this study, matrix-assisted laser desorption ionization (MALDI) tandem time-of-flight (TOF) mass spectrometry (MS/MS) and reverse genetics were used to isolate a new cDNA sequence that encodes for a protein assembled into egg case silk from the black widow spider, Latrodectus hesperus. Analysis of the primary sequence of this protein reveals approximately 52% identity to the egg case protein 1 (ECP-1) fibroin-like family member. On the basis of the similarity in the primary sequence and expression pattern, we have named this factor egg case protein 2 (ECP-2). Alignments of ECP-1 and ECP-2 demonstrate highly conserved N termini, with 16 Cys residues found within the first 153 amino acids. Traditional ensemble repeats found within reported fibroins were poorly represented in the primary sequence of ECP-2, but scattered blocks of polyalanine were present, along with a C terminus rich in GA repeats. Reverse transcription quantitative PCR analysis showed that ECP-2 is predominantly expressed in the tubuliform gland. Relative to ECP-1, ECP-2 mRNA levels were determined to be >2-fold higher. MALDI MS/MS analysis of peptide fragments generated from the large-diameter core fiber after enzymatic digestion and acid hydrolysis demonstrated the presence of a fiber that is trimeric in nature, containing tubuliform spidroin 1 (TuSp1), ECP-1, and ECP-2. We also report an additional primary sequence for TuSp1, demonstrating that TuSp1 contains two Cys residues within a nonrepetitive N-terminal region. In combination with the distinctive protein architectures of ECP-1 and ECP-2, along with their co-localization with TuSp1 in the core fiber, our findings suggest that ECP-1 and ECP-2 play important structural roles in the egg case silk fiber.

Authors+Show Affiliations

Department of Chemistry, University of the Pacific, Stockton, California 95211, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

16533031

Citation

Hu, Xiaoyi, et al. "Spider Egg Case Core Fibers: Trimeric Complexes Assembled From TuSp1, ECP-1, and ECP-2." Biochemistry, vol. 45, no. 11, 2006, pp. 3506-16.
Hu X, Kohler K, Falick AM, et al. Spider egg case core fibers: trimeric complexes assembled from TuSp1, ECP-1, and ECP-2. Biochemistry. 2006;45(11):3506-16.
Hu, X., Kohler, K., Falick, A. M., Moore, A. M., Jones, P. R., & Vierra, C. (2006). Spider egg case core fibers: trimeric complexes assembled from TuSp1, ECP-1, and ECP-2. Biochemistry, 45(11), pp. 3506-16.
Hu X, et al. Spider Egg Case Core Fibers: Trimeric Complexes Assembled From TuSp1, ECP-1, and ECP-2. Biochemistry. 2006 Mar 21;45(11):3506-16. PubMed PMID: 16533031.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Spider egg case core fibers: trimeric complexes assembled from TuSp1, ECP-1, and ECP-2. AU - Hu,Xiaoyi, AU - Kohler,Kristin, AU - Falick,Arnold M, AU - Moore,Anne M F, AU - Jones,Patrick R, AU - Vierra,Craig, PY - 2006/3/15/pubmed PY - 2006/5/17/medline PY - 2006/3/15/entrez SP - 3506 EP - 16 JF - Biochemistry JO - Biochemistry VL - 45 IS - 11 N2 - Spider silk proteins are well-known for their extraordinary mechanical properties, displaying remarkable strength and toughness. In this study, matrix-assisted laser desorption ionization (MALDI) tandem time-of-flight (TOF) mass spectrometry (MS/MS) and reverse genetics were used to isolate a new cDNA sequence that encodes for a protein assembled into egg case silk from the black widow spider, Latrodectus hesperus. Analysis of the primary sequence of this protein reveals approximately 52% identity to the egg case protein 1 (ECP-1) fibroin-like family member. On the basis of the similarity in the primary sequence and expression pattern, we have named this factor egg case protein 2 (ECP-2). Alignments of ECP-1 and ECP-2 demonstrate highly conserved N termini, with 16 Cys residues found within the first 153 amino acids. Traditional ensemble repeats found within reported fibroins were poorly represented in the primary sequence of ECP-2, but scattered blocks of polyalanine were present, along with a C terminus rich in GA repeats. Reverse transcription quantitative PCR analysis showed that ECP-2 is predominantly expressed in the tubuliform gland. Relative to ECP-1, ECP-2 mRNA levels were determined to be >2-fold higher. MALDI MS/MS analysis of peptide fragments generated from the large-diameter core fiber after enzymatic digestion and acid hydrolysis demonstrated the presence of a fiber that is trimeric in nature, containing tubuliform spidroin 1 (TuSp1), ECP-1, and ECP-2. We also report an additional primary sequence for TuSp1, demonstrating that TuSp1 contains two Cys residues within a nonrepetitive N-terminal region. In combination with the distinctive protein architectures of ECP-1 and ECP-2, along with their co-localization with TuSp1 in the core fiber, our findings suggest that ECP-1 and ECP-2 play important structural roles in the egg case silk fiber. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/16533031/Spider_egg_case_core_fibers:_trimeric_complexes_assembled_from_TuSp1_ECP_1_and_ECP_2_ L2 - https://dx.doi.org/10.1021/bi052105q DB - PRIME DP - Unbound Medicine ER -