Positional scanning library

Positional scanning library | Site-directed mutagenesis peptide library | Structure-activity relationship study | Amino acid substitution library | Science-Peptide

Need to perform site-directed scanning to identify key amino acids? Science-Peptide provides professional positional scanning library synthesis services, allowing each position in your target sequence to be individually mutated to specified amino acids (Ala, Ser, D-type, etc.), with rapid delivery and comprehensive data. Feel free to consult us.

What is a Positional scanning library?
Anyone doing structure-activity relationship studies knows that the most direct way to understand the contribution of each amino acid to activity is to substitute them one by one and test individually.

 

Positional scanning library is designed for this purpose - to individually substitute each position in your target sequence with a specified amino acid (such as alanine, serine, glycine, or D-amino acids), and then measure the activity. If the activity changes upon substitution at a certain position, it indicates that this position is crucial.

 

Going further than alanine scanning, you can choose different substitution methods:

• Alanine scanning: The most common approach, chopping off the side chain to see whether the original side chain is important.
• Conservative substitution: Replace with an amino acid of similar properties (e.g., Ser for Thr) to see if the chemical nature of the side chain is important.
• Non-conservative substitution: Replace with an amino acid of completely different properties (such as charged to hydrophobic) to see the effect of extreme changes.
• D-amino acid substitution: Test whether spatial conformation is important.
• Stepwise truncation: Remove amino acids one by one from the N- or C-terminus to determine the minimal active fragment.

1. Multiple Mutation Types, Selected as Needed

2. Library Design: One Peptide for Each Position

Control peptide Wild-type sequence (optional)
For example: If you have a peptide with 10 amino acids and want to perform alanine scanning, you need 10 peptides, each with one position substituted by Ala. For D-amino scanning, you also need 10 peptides, each with one position replaced by a D-amino acid.

3. Synthesis Capability

4. Quality control: Each peptide has its own data
For every peptide in the positional scanning library, we provide:
MS (mass spectrometry): To confirm the correct molecular weight (all variations after mutation are calculated).
HPLC purity: Data on crude or purified peptide purity.
COA report: One for each peptide, searchable by position.

Optional services:

Peptide content determination: Choose this for accurate quantification

Solubility test: Recommend suitable solvents

Amino acid composition analysis: Verify mutation accuracy

1. We've been doing this for 20 years
Although the positional scanning library sounds like "a batch of mutant peptides," there is a lot to do: each position must be synthesized separately, purity must be consistent, and mutations must be confirmed. Over the years, we've helped clients with all kinds of scanning libraries, from alanine to D-type, from conservative substitutions to truncations - our workflow is well established.

2. Multiple mutation types, all possible
Some companies can only do alanine scanning, and they get stuck with other mutation types. We're different:
D-amino acid incorporation: Added directly during solid-phase synthesis; no need for you to handle it yourself.
Non-natural amino acids: As long as you provide the structure, we can add them
Complex modifications: Scanning with modifications (such as phosphorylation, fluorescent labeling) is also feasible

3. Purity as needed, no wasted money
Crude peptides (70-85%): For initial screening, quickly see which positions have significant effects, cost-saving.
Standard purity (85-95%): Suitable for most activity assays, cost-effective option.
High purity (95-98%): Needed for precise quantification or structural studies, more reliable results.

4. Complete data, trustworthy results
We provide the MS and HPLC data for each peptide, organized in Excel, showing which position corresponds to which peptide, mutation type, purity, and molecular weight - all clear at a glance. You can use this directly when writing your publications.

5. Need modifications? We can add them too
Some experiments require labeled peptides for detection:
Biotin labeling: Convenient for capture or detection
FITC labeling: For fluorescence detection use.
Phosphorylation modification: Study phosphorylation-dependent activity
Added directly during synthesis, so you don't have to do it yourself afterwards.

6. From scanning to validation, follow through every step
After the key positions are identified, more follow-up work is often needed: such as synthesizing combination mutations, scaling up for animal experiments, or process development. Science-Peptide can seamlessly handle all these phases-one project, one contact person, no need for repeated coordination.

Delivery format:
Individual centrifuge tubes (as needed)

Accompanying documents:
Excel summary table (all peptide sequences, MW, purity, MS file links).
Independent COA (PDF) for each peptide.
Library design summary report (specifying the position and type of each mutation)
Optional: Solubility data, peptide content assay
Before sending out every positional scanning library, we double-check to ensure the mutation sites are correct, peptide numbers match, and the data is complete.

Whether you need alanine scanning, D-type scanning, or conservative substitutions, we can help you design and synthesize high-quality positional scanning libraries.
Information I need from you:
Target sequence (peptide or protein fragment)
Scanning types (alanine, D-type, conservative substitutions, etc.)
Scanning range (full length or specific region)

Do you need to include a wild-type control?
Required amount for each peptide
Purity requirement
Need for modifications (biotin, FITC, etc.)

When do you need it?

A quotation and delivery plan will be provided within 24 hours.