trometry - based proteomics: “ The mass analyzer is, literally and fi guratively,
central to the technology. ”^59 From the perspective of proteomic and systems
biology analyses, MS – MS spectrometry offers sensitivity, resolution, mass
accuracy, and the ability to generate information - rich mass spectra from
peptide fragments. The interested reader will fi nd a wealth of information on
applying mass spectrometry to proteomics in this publication.
In an accompanying article in Nature in 2003, researchers discuss some of
the long - term challenges of proteomics and describe technologies and strate-
gies, both in place and emerging, that rise to these challenges.^60 One method,
intended to detect protein – protein interactions, involves the use of fl uores-
cence resonance energy transfer (FRET) between fl uorescent tags on interact-
ing proteins. FRET is a nonradiative process whereby energy from an excited
donor fl uorophore is transferred to an acceptor fl uorophore that is within
∼ 60 Å of the excited fl uorophore. After excitation of the fi rst fl uorophore,
FRET is detected either by emission from the second fl uorophore using appro-
priate fi lters, or by alteration of the fl uorescence lifetime of the donor. Accord-
ing to the reference 60 authors, the potential of FRET is considerable, for two
reasons. First, it can be used to make measurements in living cells, which allows
the detection of protein interactions at the location in the cell where they
normally occur, in the presence of the normal cellular milieu. Second, transient
interactions can be followed with high temporal resolution in single cells. The
reference 60 authors include several examples of FRET analyses in this pub-
lication. They conclude that FRET methods are becoming practical adjuncts
in many proteomic arenas and believe, in addition to the above - mentioned
applications, that FRET could be used to monitor post - translational modifi ca-
tions and other cellular behaviors of interest.
3.8 Summary and Conclusions,
This chapter has provided an introduction to some instrumental methods used
in bioinorganic chemistry with emphasis on methods referred to in later chap-
ters. The structural methods of X - ray crystallography (solid state) and NMR
(in solution) have proved indispensable to researchers study complex bioin-
organic systems. M ö ssbauer spectroscopy is an invaluable aid for researchers
studying bioinorganic systems containing iron. Electron paramagnetic reso-
nance methods provide information on the many bioinorganic systems con-
taining unpaired electrons. Fast and time - resolved methods help bioinorganic
chemists identify short - lived catalytic intermediates and, thus, better under-
stand the catalytic cycles of metalloenzymes. Mass spectrometry experiments
have been developed to fi nd and confi rm many properties of proteins, includ-
ing how it folds into its fi nal, native conformation.
The descriptions in this chapter have attempted to give students some idea
of the scope and complexity of instrumental techniques available to the bioin-
organic chemist. It has not been intended to be either comprehensive or overly
SUMMARY AND CONCLUSIONS 153