@article {4030,
	title = {Acid-induced denaturation of myoglobin studied by time-resolved electrospray ionization mass spectrometry},
	journal = {Biochemistry},
	volume = {36},
	number = {21},
	year = {1997},
	note = {ISI Document Delivery No.: XB321Times Cited: 74Cited Reference Count: 43},
	month = {May},
	pages = {6448-6454},
	type = {Article},
	abstract = {The acid-induced denaturation of holo-myoglobin (hMb) following a pH-jump from 6.5 to 3.2 has been studied by electrospray ionization (ESI) mass spectrometry in combination with a continuous flow mixing technique (time-resolved ESI MS). Different protein conformations are detected by the different charge state distributions that they generate during ESI. The changes in intensity of the peaks in the mass spectrum as a function of time can be described by two exponential lifetimes of 0.38 +/- 0.06 s and 6.1 +/- 0.5 s, respectively. The acid-induced denaturation of hMb was also studied in stopped-flow experiments by monitoring changes in the Soret absorption. The lifetimes measured by this method are in good agreement with those obtained by time-resolved ESI MS. The shorter lifetime is associated with the formation of a transient intermediate which shows the mass of the intact heme-protein complex but leads to the formation of much higher charge states during ESI than native hMb at pH 6.5. This form of hMb has an absorption spectrum similar to that of the native protein, indicating a relatively unperturbed chromophore environment inside the heme binding pocket. The intermediate can thus be characterized as an unfolded form of hMb with essentially intact heme-protein interactions. The longer of the two lifetimes is associated with the formation of a product which has a blue-shifted absorption spectrum with a much lower maximum absorption coefficient than observed for native hMb. In the ESI mass spectrum, this product appears as the apoprotein with high charge states which indicates the disruption of the native heme-protein interactions and a considerable degree of unfolding compared to native apo-myoglobin. The mechanism of acid-induced denaturation of hMb, therefore, appears to follow the sequence (heme protein)(native) {\textendash}> (heme-protein)(unfolded) {\textendash}> heme + (protein)(unfolded).},
	keywords = {APOMYOGLOBIN, HEME-PROTEINS, INTERMEDIATE, IONS, LOW PH, METMYOGLOBIN, PROBING CONFORMATIONAL-CHANGES, RESOLUTION, SPERM WHALE, STABILITY},
	isbn = {0006-2960},
	url = {<Go to ISI>://A1997XB32100022},
	author = {Konermann, L. and Rosell, F. I. and Mauk, A. G. and Douglas, D. J.}
}
@article {3831,
	title = {Interaction of derivatized capped iron(II) porphyrin complexes with CO and O-2},
	journal = {Inorganic Chemistry},
	volume = {35},
	number = {22},
	year = {1996},
	note = {ISI Document Delivery No.: VP449Times Cited: 5Cited Reference Count: 51},
	month = {Oct},
	pages = {6539-6545},
	type = {Article},
	abstract = {{A series of porphyrins strapped and capped by benzene and amidobenzene rings have been prepared. O-2 and CO bindings to their iron(II) complexes have been examined, and the role of hydrogen-bonding in stabilizing O-2 binding has been measured. Each comparison between the benzene ring (no H-bonding) and the amidobenzene ring analogues showed a free energy gain of similar to 1 kcal/mol (at -45 degrees C) for the amidobenzene derivatives. An X-ray structure analysis was carried out for the ferric (Cl-) complex of the benzene-capped porphyrin strapped by two butyl side chains. The crystals were monoclinic, with a = 10.557(3) Angstrom},
	keywords = {CARBON-MONOXIDE BINDING, cobalt, CRYSTAL-STRUCTURE, CYCLOPHANE HEMES, DIOXYGEN BINDING, DISTAL POLAR, HEME-PROTEINS, HUMAN OXYHEMOGLOBIN, LIGAND-BINDING, MYOGLOBINS, O2 BINDING},
	isbn = {0020-1669},
	url = {<Go to ISI>://A1996VP44900026},
	author = {Tang, H. and Dolphin, D.}
}
