Protein profiling
State-of-the-art technologies that analyse body proteins quickly and accurately could provide a valuable new weapon in the fight against crime, reports Damian Small.
State-of-the-art technologies that analyse body proteins quickly and accurately could provide a valuable new weapon in the fight against crime, reports Damian Small.
Dr Mikhail Soloviev of the School of Biological Sciences at Royal London Holloway, London University, is leading an initiative that assesses technologys potential to take body tissue/fluid samples recovered from crime scenes, and use them to generate crucial information that can help identify criminals and their victims.
Whilst DNA can be matched against databases relatively easily, in the absence of a match, tissue samples, body fluids or stains may still reveal vital intelligence information useful for fitting the persons biometrical or behavioural profiles or for gathering additional forensic information. Protein and metabolite profiles are more representative of, the state of health, lifestyle, behavioural patterns, the severity and type of trauma or the cause of death.
Dr Soloviev added: We have looked at the scope for harnessing two innovative technologies: protein micro-arrays and peptidomics, for forensic use. Our study has shown that these could potentially be deployed in criminal investigations within around 3 years.
He gave examples of how a table of protein markers would aid intelligence in the field. Analysis of blood stains for Beta-enolase, Fibrinogen Degradation Products, Myoglobin, Matrix metalloproteinase(s) and HLA-DR (human leukocyte antigens) might reveal whether:
The bloodstain came from trauma or was non-traumatic.
The blood came from a victim whilst the victim was alive or it originates from a cadaver.
The blood was from an adult or a neonate.
The trauma/blood stain happened at night, whilst at sleep, or during daytime.
Tissue specific protein markers will reveal which part of the body the traumatic blood came from.
Blood stains or samples from survived victims would contain markers capable to help in the timing and severity of the trauma.
The initiative utilises forensic and biometric protein markers, microarray techniques and a peptidomics approach in gaining behavioural profiles and additional forensics information.
We developed a peptide antigenicity prediction algorithm. Antipeptide antibodies are traditionally sought where full-length protein sequences are not available, these antibodies are often used to assay/isolate/detect parent proteins rather then peptides.
We have therefore designed a prototype software which performs in silico proteolysis, selects common or unique peptides for a group of supplied sequences, and ranks peptides in order of immunogenicity: ability of molecule to elicit an immune response.
Ranking takes into the account the parameters, which are relevant to protein synthesis and stability. The design of this tool was instrumental in allowing fast progress of this project. We intend to continue our work on this during the next 6-9 months, and intend to publish the results and the programme in due course.
Dr Soloviev gave details of the peptide markers suitable for use in biometrics and forensic applications.
We have originally decided to choose 20 peptides to generate pan-HLA antipeptide antibodies for each of the major HLA specifities recognised to date. However, the majority of peptides can be found in more than one individual HLA.
Therefore, we used protein/peptide markers other than HLA antigens and surveyed 15 years worth of forensic literature. Our marker section consists of the five categories:
Biometrics
Blood origin
Lifestyle
Time of death
Trauma and death
Once the effect sizes from individual studies are calculated and converted into a single index, they can be combined across studies and compared among groups to determine the relative efficiency of different proteins as markers of specific conditions or the relative efficiency of the same marker with respect to indi