About: Myoglobin is a research topic. Over the lifetime, 4377 publications have been published within this topic receiving 151708 citations. The topic is also known as: uniprot:P02144 & MB.
Papers published on a yearly basis
01 Jan 1971
TL;DR: Kendrew et al. as mentioned in this paper used Max Perutz's technique to produce the first 3D images of any protein -myoglobin, the protein used by muscles to store oxygen.
Abstract: To understand how a protein performs its individual biological function, it is essential to know its three-dimensional structure As early as 1934, JD Bernal and Dorothy Hodgkin (then Dorothy Crowfoot) showed [Bernal, J D & Crowfoot, D Nature 133, 794–795 (1934)] that proteins, when crystallized, would diffract X-rays to produce a complex pattern of spots They knew that these patterns contained all the information needed to determine a protein–s structure but, frustratingly, that information could not be deciphered By comparing patterns from crystals containing different heavy-metal atoms, Max Perutz and colleagues devised the approach that was to solve this riddle In 1958, J C Kendrew et al applied Perutz–s technique to produce the first three-dimensional images of any protein - myoglobin, the protein used by muscles to store oxygen
TL;DR: The nonexponential rebinding observed at low temperatures and in solid samples implies that the innermost barrier has a spectrum of activation energies, similar to how myoglobin achieves specificity and order.
Abstract: Myoglobin rebinding of carbon monoxide and dioxygen after photodissociation has been observed in the temperature range between 40 and 350 K. A system was constructed that records the change in optical absorption at 436 nm smoothly and without break between 2 musec and 1 ksec. Four different rebinding processes have been found. Between 40 and 160 K, a single process is observed. It is not exponential in time, but approximately given by N(t) = (1 + t/to)-n, where to and n are temperature-dependent, ligand-concentration independent, parameters. At about 170 K, a second and at 200 K, a third concentration-independent process emerge. At 210 K, a concentration-dependent process sets in. If myoglobin is embedded in a solid, only the first three can be seen, and they are all nonexponential. In a liquid glycerol-water solvent, rebinding is exponential. To interpret the data, a model is proposed in which the ligand molecule, on its way from the solvent to the binding site at the ferrous heme iron, encounters four barriers in succession. The barriers are tentatively identified with known features of myoglobin. By computer-solving the differential equation for the motion of a ligand molecule over four barriers, the rates for all important steps are obtained. The temperature dependences of the rates yield enthalpy, entropy, and free-energy changes at all barriers. The free-energy barriers at 310 K indicate how myoglobin achieves specificity and order. For carbon monoxide, the heights of these barriers increase toward the inside; carbon monoxide consequently is partially rejected at each of the four barriers. Dioxygen, in contrast, sees barriers of about equal height and moves smoothly toward the binding site. The entropy increases over the first two barriers, indicating a rupturing of bonds or displacement of residues, and then smoothly decreases, reaching a minimum at the binding site. The magnitude of the decrease over the innermost barrier implies participation of heme and/or protein. The nonexponential rebinding observed at low temperatures and in solid samples implies that the innermost barrier has a spectrum of activation energies. The shape of the spectrum has been determined; its existence can be explained by assuming the presence of many conformational states for myoglobin. In a liquid at temperatures above about 230 K, relaxation among conformational states occurs and rebinding becomes exponential.
TL;DR: In this paper, anilino-8-naphthalene sulfonate (ANS) was used as a fluorescent probe of non-polar regions in proteins and its fluorescence changes markedly when it is bound to the apoprotein.
TL;DR: The dynamical behaviour of myoglobin (and other globular proteins) suggests a coupling of fast local motions to slower collective motions, which is a characteristic feature of other dense glass-forming systems.
Abstract: Structural fluctuations in proteins on the picosecond timescale have been studied in considerable detail by theoretical methods such as molecular dynamics simulation1,2, but there exist very few experimental data with which to test the conclusions. We have used the technique of inelastic neutron scattering to investigate atomic motion in hydrated myoglobin over the temperature range 4–350 K and on the molecular dynamics timescale 0.1–100 ps. At temperatures below 180 K myglobin behaves as a harmonic solid, with essentially only vibrational motion. Above 180 K there is a striking dynamic transition arising from the excitation of non-vibrational motion, which we interpret as corresponding to tor-sional jumps between states of different energy, with a mean energy asymmetry of KJ mol −1. This extra mobility is reflected in a strong temperature dependence of the mean-square atomic displacements, a phenomenon previously observed specifically for the heme iron by Mossbauer spectroscopy3–5, but on a much slower timescale (10−7 s). It also correlates with a glass-like transition in the hydration shell of myoglobin6 and with the temperature-dependence of ligand-binding rates at the heme iron, as monitored by flash photolysis7. In contrast, the crystal structure of myoglobin determined down to 80 K shows no significant structural transition8–10. The dynamical behaviour we find for myoglobin (and other globular proteins) suggests a coupling of fast local motions to slower collective motions, which is a characteristic feature of other dense glass-forming systems.
Trending Questions (10)