Recombinant Enterobacter sp. Probable intracellular septation protein A (Ent638_2285)

What is Ent638_2285 and what is its primary function?

Ent638_2285, also known as YciB or Inner membrane-spanning protein YciB, is a probable intracellular septation protein found in Enterobacter species. It is a 179-amino acid membrane protein (UniProt ID: A4WB74) that appears to be involved in bacterial cell division processes and potentially in metabolite transport . The protein is thought to contribute to maintaining proper cell shape and division symmetry, as mutations in similar proteins have been shown to affect these processes in related bacterial species .

What is the amino acid sequence of recombinant Ent638_2285?

The full amino acid sequence of Ent638_2285 (1-179aa) is:
MKQFLDFLPLVVFFAFYKLYDIYAATTALIVATAIVLIYTWIRYRKVEKMALITFVLVAVFGGLTVFFHNDEFIKWKVTVIYGLFAGALLFSQWVMNKPLIQRMLGKEITLPQEVWSRLNIAWAVFFILCGLANIYIAFWMPQNIWVNFKVFGLTALTLIFTLLSGVYIYKHMPQDDKH

This sequence reveals characteristics of a transmembrane protein with hydrophobic regions consistent with its proposed localization in the inner membrane.

How does Ent638_2285 relate to bacterial shape maintenance?

While direct experimental evidence for Ent638_2285 is limited in the available literature, research on similar inner membrane proteins suggests it may play a role in maintaining bacterial cell shape. Studies on related proteins indicate that mutations in inner membrane proteins can lead to shape abnormalities and affect cell division processes . In various bacteria, proper shape maintenance is crucial for accurate chromosome segregation and cell division, with abnormalities potentially leading to increased rates of anucleate cells or other division defects .

What expression system is recommended for recombinant Ent638_2285?

Recombinant Ent638_2285 has been successfully expressed in E. coli expression systems with an N-terminal His tag . For optimal expression of this membrane protein, consider the following methodology:

• Use specialized E. coli strains designed for membrane protein expression (e.g., C41(DE3), C43(DE3))

• Express at lower temperatures (16-25°C) to reduce inclusion body formation

• Consider IPTG concentrations between 0.1-0.5 mM for induction

• Extend expression time to 16-24 hours at lower temperatures

This approach helps balance protein yield with proper folding of the membrane protein.

What purification strategy provides highest purity for His-tagged Ent638_2285?

A multi-step purification approach is recommended:

• Cell lysis using appropriate detergents (e.g., n-dodecyl β-D-maltoside or CHAPS) to solubilize membrane proteins

• Initial purification using Ni-NTA affinity chromatography with imidazole gradient elution

• Size exclusion chromatography to remove aggregates and contaminants

• Optional ion exchange chromatography for highest purity

This strategy has been shown to yield protein with purity greater than 90% as determined by SDS-PAGE .

What are the optimal storage conditions for maintaining Ent638_2285 stability?

Based on the product information, the following storage protocol is recommended:

• Store lyophilized protein at -20°C/-80°C upon receipt

• Reconstitute in deionized sterile water to 0.1-1.0 mg/mL

• Add glycerol to 5-50% (50% recommended) final concentration

• Aliquot and store at -20°C/-80°C for long-term storage

• Avoid repeated freeze-thaw cycles

• Working aliquots may be stored at 4°C for up to one week

This protocol helps maintain protein stability and prevents degradation during storage.

How can researchers assess Ent638_2285's role in bacterial cell division?

To investigate Ent638_2285's function in cell division, researchers should consider a multi-faceted approach:

• Gene knockout/knockdown studies:

  • Generate Ent638_2285 deletion mutants

  • Quantify changes in cell morphology, division frequency, and septum formation

  • Measure anucleate cell formation rates (normally <0.03% in wild-type vs. potentially higher in mutants)

• Protein localization:

  • Create fluorescent protein fusions (e.g., GFP-Ent638_2285)

  • Use super-resolution microscopy to track localization during the cell cycle

  • Co-localization studies with known septation proteins

• Complementation assays:

  • Express wild-type Ent638_2285 in knockout strains to confirm phenotype rescue

  • Test point mutations to identify essential functional residues

These approaches would provide insights into whether Ent638_2285 influences cell division similar to other intracellular septation proteins.

What approaches can determine if Ent638_2285 functions in metabolite transport?

Research suggests Ent638_2285/YciB may be involved in metabolite transport . To investigate this function:

• Transport assays:

  • Compare uptake rates of various radiolabeled metabolites in wild-type vs. Ent638_2285 mutants

  • Measure changes in membrane potential using fluorescent dyes

• Protein-protein interaction studies:

  • Perform pull-down assays to identify interaction partners

  • Use bacterial two-hybrid systems to screen for interactions with known transporters

• Metabolomic profiling:

  • Compare intracellular and extracellular metabolite profiles between wild-type and mutant strains

  • Look for specific metabolite classes that show altered concentrations

This systematic approach would help characterize any transport function of Ent638_2285.

How does Ent638_2285 relate to bacterial resistance mechanisms?

Research indicates YciB (Ent638_2285) may be linked to resistance against contact-dependent growth inhibition (CDI) toxins . Investigators can explore this connection through:

• Resistance development assays:

  • Challenge bacteria with CDI toxins and select for resistant mutants

  • Sequence yciB/Ent638_2285 in resistant strains to identify protective mutations

• Protein-toxin interaction studies:

  • Assess direct binding between purified Ent638_2285 and CDI toxins

  • Perform competition assays with wild-type and mutant strains expressing different levels of Ent638_2285

• Mechanistic investigations:

  • Determine if Ent638_2285 acts as a receptor for toxin entry

  • Investigate whether it functions in a complex with other membrane proteins to confer resistance

Understanding this function could provide insights into bacterial competition mechanisms and potential antimicrobial targets.

What is the relationship between Ent638_2285 and bacterial morphology?

To explore connections between Ent638_2285 and bacterial shape:

• Morphometric analysis:

  • Track changes in cell length, width, and aspect ratio in Ent638_2285 mutants

  • Quantify cell volume to DNA volume ratios, which may decrease upon CdiA-CT2 induction as observed with similar proteins

• Cell wall analysis:

  • Examine peptidoglycan synthesis patterns in mutants vs. wild-type

  • Investigate localization relative to cell wall synthesis machinery

• Cytoskeletal interactions:

  • Assess relationships with bacterial cytoskeletal proteins like MreB

  • Investigate if Ent638_2285 disruption affects chromosome segregation similar to other shape-determining proteins

Established research shows that similar membrane proteins, when mutated, can cause cells to grow as irregularly sized spheres instead of rods, with reduced chromosome segregation accuracy .

How can researchers overcome aggregation issues during Ent638_2285 purification?

Membrane protein aggregation is a common challenge. Implement these strategies:

• Optimize detergent selection:

  Detergent Class	Examples	Recommended Concentration
  Mild non-ionic	DDM, DM	1-2× CMC
  Zwitterionic	CHAPS, FC-12	0.5-1% w/v
  Steroid-based	Digitonin	0.1-0.5% w/v

• Solubilization optimization:

  • Test different detergent-to-protein ratios

  • Include stabilizing agents (glycerol, specific lipids)

  • Evaluate solubilization at different temperatures (4°C vs. room temperature)

• Purification modifications:

  • Add detergent to all buffers above CMC

  • Include lipids or amphipols for protein stabilization

  • Consider on-column refolding techniques

These approaches can significantly reduce aggregation while maintaining protein structure and function.

How can contradictory findings about Ent638_2285 function be reconciled?

Researchers encountering contradictory results should consider:

• Strain-specific differences:

  • Compare protein sequences across strains to identify variations

  • Assess genetic background effects by complementation in multiple strains

• Experimental condition variations:

  • Standardize growth conditions (media, temperature, growth phase)

  • Document all buffer compositions and experimental parameters precisely

• Functional redundancy:

  • Investigate potential backup systems that may mask phenotypes

  • Create double or triple mutants of functionally related genes

• Technical considerations:

  • Validate antibody specificity for detection experiments

  • Confirm knockout/knockdown efficiency using multiple methods

  • Use appropriate statistical analyses for subtle phenotypes

This systematic approach helps distinguish true biological variations from technical artifacts.