Phospho-specific antibodies by LifeTein published in Nature

Jia Shen. et al. EGFR modulates microRNA maturation in response to hypoxia through phosphorylation of AGO2. Nature 497, 383–387 (16 May 2013), doi:10.1038/nature12080 LifeTein helped designed and synthesized a series of phosphorylated s. Then the peptides were used for phospho-specific productions. The phospo-specific antibodies by LifeTein were confirmed to react with the epidermal growth factor receptor (EGFR). The Hung’s lab showed that AGO2-Y393 phosphorylation mediates EGFR-enhanced cell survival and invasiveness under hypoxia. These findings suggest that modulation of miRNA biogenesis is important for stress response in tumour cells. … The following peptides were chemically synthesized for in mice (Lifetein Conc.), Elisa verification (LifeteinConc.) and peptide competition assay in immunohistochemistry (IHC)… Supplementary information

Synthesis of multiple antigenic peptides:strategies and limitations

Synthesis of multiple antigenic peptides: strategies and limitations

Dendrimeric platforms such as MAPs can be synthesized by solid phase method or by conjugation . Dendrimeric platforms such as MAPs can be synthesized either entirely by solid-phase methods (SPPS, direct approach) or by conjugation in solution of preformed, SPPS-made building blocks (indirect approach).

MAP peptide synthesis

MAP peptide synthesis

http://www.ncbi.nlm.nih.gov/pubmed/21391284

SPPS is the preferred method by LifeTein. The synthesis approach requires a branched poly-lysine core. Each branch is elongated into the corresponding epitope by stepwise SPPS. The disadvantage of this approach is that the synthetic errors could happened and cause microheterogeneity in the final materials. However the cost is lower and less time-consuming than the indirect approach. For very long linear peptides, it is more advantageous to use the SPPS method.

The MAP synthesis may not always meet with success. The solubility of the peptide epitope can also become an issue and is difficult to predict for long epitopes. It is recommended to carefully design and analyze the linear epitope before MAP synthesis.

Studies showed that synthesis with Ahx linker in the lysine core had better isolated yield. It is possible that the flexibilizing effect of Ahx helps in keeping peptide chains properly solvated during synthesis, preventing aggregation and hence increasing the amount of viable growing peptide sequences.

 

The Structural Basis of Peptide-Protein Binding Strategies

peptide protein binding strategy

Peptide protein binding strategies: Structure, Volume 18, Issue 2, 188-199, 10 February 2010

 

Highlights

  • Most peptides do not induce conformational changes on their partner upon binding
  • Peptide-protein interfaces are better packed and contain more hydrogen bonds
  • Binding is mediated by peptide hotspots that contribute most of the binding energy
  • Peptides tend to bind in the largest pockets or holes on the protein surface

Read more from here.

LifeTein is pleased to offer a free, comprehensive web-based peptide analysis tool. This tool will allow your research team to overcome common difficulties inherent in protein analysis and peptide antigen design.

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Peptide analysis tool-LifeTein

D-amino acid peptides to resist common proteases

Peptides that are at least partially made of D-amino acids have shown strong resistance to proteolytic degradation.

D amino acid peptide with high stability

D amino acid peptide with high stability

See more details from here: http://lifetein.com/Peptide-Synthesis-D-Amino-Acid.html

Reference: http://www.pnas.org/content/102/2/413.full.pdf+html

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Amino acid composition of cell-penetrating peptides (CPPs)

Cell-penetrating peptides (CPPs) such as the HIV TAT peptides are able to enter cell by direct translocation and endocytosis. Click here to see details about the CPP: http://lifetein.com/Cell_Penetrating_Peptides.html

cell penetrating peptide entry mechanism

Cell Penetrating Peptides

The following table shows a selection of currently known CPPs, their origins and sequences.

Name

Origin

Sequence

Tat family
Tat (48-60)

HIV-1 protein

GRKKRRQRRRPPQQ

     Oligoarginine

Tat derivative

Rn

Penetralia family
     p-Antp

Antermapedia homeodomain

RQIKIWFQNRRMKWKK

     plsl

Igl-1 homeodomain

RVIRVWFQNKRCKDKK

Chimeric CPPs
     Transportan

Galanin-mastoparan

GWTLNSAGYLLGKINLKALAALAKKIL

MPG peptides
     P-beta

gp41-SV40

GALFLGFLGAAGSTMGAWSQPKKKRKV

     P-alpha

gp41-SV40

GALFLAFLAAALSLMGLWSQPKKKRRV

Pep-1

Trp-rich motif-SV40

KETWWETWWTEWSQPKKKRRV

STR-Cpps

STR-R8

Stearly-RRRRRRRR-amide
(Stearyl = CH3(CH2)16CO-)

STR-(RxR)4

Stearly-(RxR)4-amide
(X=6-aminohexanoic acid)

STR-TP10

Stearly-AGYLLGKINLKALAALAKKIL-amide

PF14

Stearly-AGYLLGKLLOOLLAAAALOOLL-amide (O=ornithine)

NickFect1

Stearly-AGY(PO3)LLGKTNLKALAALAKKIL-amide

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Obesity Treatment: A New Peptide Drug

Targeted Drug Melts Fat in Obese Monkeys

During the past 20 years, there has been a dramatic increase in obesity in the United States and rates remain high. In 2010, no state in the United States had a prevalence of obesity less than 20%. Approximately one in three adults and one in six children are obese. Obesity is epidemic in the United States today and a major cause of death, attributable to heart disease, cancer, and diabetes.

Despite significant efforts in the past decade, very few drugs have been successfully developed for the treatment of obese patients. Currently, only two Food and Drug Administration (FDA) approved drugs for weight loss are available in the United States: the appetite suppressant phentermine and the inhibitor of fat absorption orlistat. Orlistat (Xenical) is a weight-loss medication for long-term weight loss. This medication blocks the digestion and absorption of fat in your stomach and intestines. Other attempts to treat obesity have also predominantly focused on drugs aimed at suppressing appetite or increasing metabolism, but these efforts have been hampered by their toxic side-effects. Unfortunately, it’s common to regain weight no matter what obesity treatment methods you try.

In contrast, an MD Anderson group designed a new drug, the ligand-directed peptidomimetic CKGGRAKDC-GG-D(KLAKLAK)2 (termed adipotide), which is a synthetic peptide that triggers cell death. The drug acts on white adipose tissue. The white adipose tissue is the unhealthy type of fat that accumulates under the skin and around the abdomen.

In earlier preclinical research, obese mice lost about 30 percent of their body weight with this peptidomimetic peptide. Monkeys from three different species displayed predictable and reversible changes in renal proximal tubule function. Overall and abdominal body fat levels drop, with reversible renal side effects Weight, BMI and abdominal circumference all continued to drop for three weeks after treatment ended before slowly beginning to reverse during the fourth week of the follow-up period. Monkeys in the studies demonstrated no signs of nausea or food avoidance. The renal effect was dose-dependent, predictable and reversible. This is a potentially important finding since unpleasant side-effects have limited the use of approved drugs that reduce fat absorption in the intestines.

Together, these data in primates establish adipotide as a prototype in a new class of candidate drugs that may be useful for treating obesity in humans.

This is an alternative approach based on libraries of natural, highly structured peptides that offers new opportunities for identifying effective, specific inhibitors of protein-protein interactions. Peptide libraries constitute virtually all of the available classes of protein fold structures, providing a rich source of peptides that interact specifically and with high affinity to human proteins.

Using peptide library, the MD Anderson group is able to screen and identify those that bind to specific vascular cells among the many possible “ZIP codes” present in a human vascular map. This approach may help not only in understanding the implications of each interaction identified within the interactome but also in the development of effective drugs targeted to particular protein functions. Although peptide libraries are active in animal models, the challenge remains to demonstrate efficacy and safety in a clinical setting.

www.cdc.gov/CDCTV/ObesityEpidemic/

This video explains the many factors that have contributed to the obesity epidemic, and showcases several community initiatives taking place to prevent and reduce obesity. Obesity is a national epidemic and a major contributor to some of the leading causes of death in the U.S., including heart disease, stroke, diabetes and some types of cancer. We need to change our communities into places that strongly support healthy eating and active living.

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Peptide Antigens from Tumor Cells: Potential Peptide Vaccines for Cancer

Check the cancer peptide database for a list of tumor peptides.

Tumor antigens can be classified into two categories based on their pattern of expression: tumor-specific antigens (TSA) and tumor-associated antigens (TAA).

Peptide Antigens

Tumor associated peptide antigens

LifeTein can customize a discovery and development path to fit your exact needs for peptide synthesis.

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Peptide Synthesis for Cell-penetration Studies

Cell-penetrating peptides (CPPs) have the ability to enter a cell’s plasma membrane independent of a membrane receptor. Attached to a CPP, therapeutic cargo could be delivered to an intracellular target, thus overcoming the entry restrictions set by the plasma membrane.

Please click here for more details for cell penetrating peptide synthesis services: http://lifetein.com/Cell_Penetrating_Peptides.html

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Synthetic Peptide Vaccine Research: Problems and Accomplishments

On October 5, 2011, Apple’s Steve Jobs died in California at age 56, seven years after being diagnosed with pancreatic cancer.

Immune-based cancer treatments are one emerging type of therapy, and they show great potential. Synthetic-peptide-based vaccines, which are designed to elicit T cell immunity, are also a promising approach to the prevention and treatment of both infectious diseases and malignant disorders, such as cancer.

Read more at:http://lifetein.com/therapeutics_peptide_applications.html
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