Part:BBa_K1694006

Gold Binding Polypeptide

Introduction

Fig.1 Gold Binding Polypeptide

The gold binding polypeptide, abbreviated as GBP, is the three-repeated of following 14 amino acid sequences MHGKTQATSGTIQS, which has developed in an E.coli cell-surface display system for several years.[1] The recent computation study demonstrated that multiple repeats of GBP have higher affinity to gold surface because of a high degree of conformational flexibility, which can make the binding much stronger. The mechanism of the connection between GBP and gold metal plane is still unknown. By using Molecular Dynamics (MD), it indicates that GBP, with the structure of antiparallel β-sheet, can recognize gold surface via OH-binding. It seems that the hydroxyl as well as amine ligands on GBP can recognize the atomic lattice of gold, aligning the molecule along the variants of a six-fold axis on the Au (111) surface.[2] A separate study also found out the fact that the water molecules played the important roles for the surface recognition by the side chain and hydration layer of the peptides to reach the better binding. [3]

Reference:
[1] Molecular characterization of a prokaryotic polypeptide sequence that catalyzes Au crystal formation, John L. Kulp III,a Mehmet Sarikayab and John Spencer Evans, Journal of Materials Chemistry(2004)
[2] Assembly of Gold-Binding Proteins for Biomolecular Recognition, Zareie HM1,2* and Sarikaya M3, Austin Journal of Biosensors & Bioelectronics (2015)
[3] Thermodynamics of Engineered Gold Binding Peptides: Establishing the Structure−Activity Relationships, Urartu Ozgur Safak Seker, Brandon Wilson, John L. Kulp,§ John S. Evans, Candan Tamerler, and Mehmet Sarikaya(2014)

Experiment

Fig.2 The PCR result of the GBP. The DNA sequence length of GBP are around 100～200 bp, so the PCR products should appear at 300～400 bp.

After receiving the DNA sequences from the gene synthesis company, we recombined each GBP gene to PSB1C3 backbones and conducted a PCR experiment to check the size of each of the GBP. The DNA sequence length of the GBP is around 100～150 bp. In this PCR experiment, the GBP products size should be near at 350～400 bp. The Fig.2 showed the correct size of the GBP, and proved that we successful ligated the GBP sequence onto an ideal backbone.

Fig.3Plate of gold binding polypeptide

Application

Our team wants to display GBP on the surface of E. coli, so we create the FadL-GBP part.

FadL

The FadL protein (48.8 kDa) is an outer membrane protein of the E. coli, which plays an important role in the uptake of exogenous long-chain fatty acid. The FadL protein has twenty antiparallel β-strands, which form a β-barrel structure and are connected by 9 internal loops and 10 external loops. Due to the β-structure, the FadL protein is able to span the outer membrane multiple times to form a long-chain fatty acid-specific channel. With these properties, the truncated FadL protein can be used as a novel anchoring motif for display of proteins on the E. coli cell surface [1].

Reference: [1]Display of Bacterial Lipase on the Escherichia coli Cell Surface by Using FadL as an Anchoring Motif and Use of the Enzyme in Enantioselective Biocatalysis, Seung Hwan Lee1, Jong-Il Choi1, Si Jae Park1,†, Sang Yup Lee1,2,* and Byoung Chul Park3(2004)

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]