Spotlight on Peptide Mass Fingerprinting
Analytical techniques can enhance material study of art and cultural heritage. Peptide mass fingerprinting (PMF) is a relatively simple biotechnology technique which we are newly applying in museums. A collaborative study with Alutiiq Alaska Native community experts, Alfred Naumoff, Sven Haakanson, and Susan Malutin, provided unexpected opportunity to consider new methods for identifying mammalian materials in their cultural historic items specifically kayaks and kayak-related accessories.
When other analytical approaches did not provide results to their materials questions, Daniel P. Kirby, conservation scientist, suggested in 2012, that we explore the potential of PMF to identify the sources of animal skin, sinew, and inner membranes. The technique uses enzymatic digestion of extracted collagen to cleave proteins at specific amino acid sites forming a unique peptide mixture. The mixture is analyzed by Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI), and then compared to a reference database of known protein sequences.
Fig. 2. Project research assistant Madeline Corona processing samples for MALDI analysis at Mass Spectrometry lab, and at right, Madeline taking a micro-sized skin sample from a pair of boots. 2015.0.22.3 and 2015.0.22.1.
Applying PMF in the study of collagen-based items assists in corroborating or expanding indigenous knowledge and augmenting previously limited museum documentation. Continued PMF research work in 2013 and 2014 contributed to an enlarged reference materials database used in interpretation, and in the training of several conservators to understand and utilize this simple analytical method. The museum continues to use PMF as a tool for identifying materials in selected objects for exhibits and loans and in finding the best means to preserve the items.
Featured below are two of the objects in which PMF has been successfully applied: an Inuit dog sledge from Greenland and an Alaskan Alutiiq skin-covered kayak.
Study of a Dog Sledge from Greenland
Fig. 3. Dog Sledge. Gift of Rear Admiral Robert E. Peary, 93-14-10/51656.
In preparation for the current exhibition All the World Is Here at the Peabody Museum, the conservation staff collaborated with Kirby to identify bone and ivory on Inuit objects from Greenland using new sampling techniques to remove minute samples. PMF confirmed and/or revealed the presence of walrus bone, walrus ivory, narwhal ivory and right whale bone in the complex construction of the dog sledge.
Fig. 4. Daniel Kirby sampling bone components of the sledge.
The results of this example highlight the significant value of PMF as an analytical tool to provide a more complete understanding about cultural materials for museum and cultural caretakers.
Fig. 5. Alutiiq warrior-whaler kayak. Museum purchase, 69-30-10/1619
This unique single-hatch Alutiiq kayak, piqued the interest of Sven Haakanson and Ronnie Lind (Alutiiq representatives from Kodiak Island, Alaska in 2003) when they were consultants to the Peabody Museum of Archaeology and Ethnology, Harvard University.
This discovery catalyzed further interest and recognition of the craft’s significance which culminated in a grant-funded project to study and conserve the Alutiiq warrior-whaler kayak, and efforts to increase its accessibility to the Alutiiq community, University, and public. The collaborations among the Peabody Museum, the Alutiiq Museum and Alutiiq consultants have generated a host of questions about the kayak. All aimed to understand the materials used in its construction and to facilitate treatment decisions and contribute to developing knowledge.
Fig. 6. Alutiiq project consultant, Susan Malutin sharing traditional cultural technologies with Harvard students and museum staff.
We understood that Alutiiq community members, especially Alaska Native artists, are similarly interested in materials and techniques. The Alutiiq Museum and community of Kodiak, AK has been particularly interested in developing knowledge around kayaks and kayak-making, and has a multi-dimensional initiative around this effort with the longer-term goals of promoting public awareness of rich cultural traditions, inspiring youth pride, and strengthening community for a sustainable future. As part of this collaborative project, minute samples of sinew and skin were taken from agreed upon locations on the warrior-whaler kayak. PMF analysis of the kayak demonstrated that the original maker(s) worked with harbor seal for the skin covering and humpback whale sinew for stitching. This information also facilitated collaborative stabilization of the kayak’s condition. Following substantial stabilization, the kayak became fit to travel to Alaska for the Alutiiq Museum’s interest to exhibit and steward. The kayak is currently on exhibit in “Qayat-Kayak” at the Alutiiq Museum, Kodiak, AK (opened in 2016).
The Alaska Native kayak study and conservation at the Peabody Museum was partially supported through a grant from the Save America’s Treasures program administered by the U.S. Institute for Museum and Library Services. Funding for the PMF research project was received from the National Park Service’s National Center for Preservation of Technology and Training. Further technical information on PMF can we found at the PM webpage and in Staff Publications.