Maximilian

Homo sapiens!

Yup, that seems about what you'd expect under those conditions! I'm glad I could help.

This question is hard to answer because it depends on how you decide to define a living thing, what cellular structures you are looking for, what you mean with genetic material, and what you mean with "basic feature". In my opinion, the answer to this question will change depending on who asks it. For example, if your professor is of the opinion that Viruses are not alive and you just went over viral genetics, then she might be looking for the answer "Cellular structure because viruses also contain genetic information and are not alive". However, perhaps your professor chose to define life as any entity that carries genetic information, and also talked about the formation of vesicles that might look like microorganisms under the microscope. In this case, he might be looking for "genetic information". It's a question which can be interpreted in many different ways, and so there is no "correct" answer.

In general, organic molecules with no conjugated double bonds will tend to be "white" because they do not absorb photons with wavelengths in the visible range, they just scatter them. The color depends between the difference in energy between the highest occupied molecular orbital ("HOMO") and the lowest unoccupied molecular orbital ("LUMO"). The HOMO-LUMO gap for the average non-conjugated organic molecule tends to found in the UV range, which is invisible to most of us. In general, as you add more PI bonds into a conjugated system, the energy required for an electron to jump from the bonding HOMO to the antibonding LUMO is reduced. Hence, adding more conjugated PI bonds to system will "red-shift" the compound. Other substituents will affect the electronics and hence the color, as well as the surrounding environment around the chromophore (for example, in fluorescent proteins with the same chromophore but different amino acids surrounding it, and all three human opsins absorb different wavelengths using the same retinal molecule). For a good treatment on MO's I recommend you Ian Flemming's Molecular Orbitals and Organic Chemical Reactions. The first chapter talks a lot about conjugation. This applies to organic molecules without metals. Metals have different electronics and often times the color of their complexes depend on the reduction state of the metal, that is, the number of electrons present in their d-orbitals. There are more complications when it comes to color, such as "why is solid elemental sulfur yellow?" or how to explain the color of some solid metals and minerals, while many of these can be explained purely with electronics of the molecular orbitals, sometimes other optical phenomenon need to be invoked (especially with more complicated materials). There's a video on it here: https://www.youtube.com/watch?v=rt3aR87SFQI Also, here's a list with the color of elements: http://www.periodictable.com/Properties/A/Color.html

How are you running your gel filtration? If there are no denaturing agents and the pH is right, it should look the same as native. In native, you are keeping the proteins in their native form. This means that the quaternary structure should remain conserved. On the SDS-PAGE you use denaturant (SDS to disrupt secondary/tertiary and a reducing agent such as beta-mercaptoethanol to reduce the disulfide bridges) to denature your protein. This will convert multimers into their monomeric form. When you run gel filtration you can choose your conditions to keep the protein native or you can also denature it. If your conditions are denaturing, the results will likely look like SDS-PAGE. Otherwise they should look like native. I am thinking your protein is a homotetramer because the small weight is approximately 1/4 of the bigger weight, but this is not necessary. If you are running the SDS-PAGE and the native after purifying the protein with a his-tag, and there is only one band in the SDS-PAGE, I would think it is a homotetramer. It is hard to know without knowing exactly what the protein has gone through and your gel filtration conditions.

The sad truth is that we currently lack the methodology to study consciousness at that level in a truly scientific manner. It is debatable whether we will ever come up with a way to do so - finger crossed!

The pKa for the imidazole conjugate acid is of around 7. You do not want your pH to go any lower than that, as the imidazole will become protonated and won't bind to the resin (might still get some elution from protonating the his-tag, but it's not very efficient). At pH 9, the imidazole will not be protonated, so it will still elute your protein. However, your protein will remain in the elution buffer, and for many proteins a pH of 9 is not optimal. I would add HCl until the pH goes down to 7.5. Add a bit, mix, measure pH. Repeat until you get to 7.5.

In general, it would not be necessary to "cancel out some existing genes", unless the specific phenotype requires it. Yes, it is possible. Simple in theory, but very, very, very complicated in practice. For example, hair thickness, color, and straightness could be modified by inserting the appropriate gene variants. I don't think the hairline location could be manipulated genetically in an adult because that involves the expression of genes during the development rather than genes being currently expressed. I mean, you could do it, but that is not simple in theory at all. You'd have better luck performing surgery.

Is your protein a tetramer? If the monomeric unit is 36.5kD that could explain the results.

From: All-D amino acid-containing channel-forming antibiotic peptides "The resistance of L- and D-cecropin A to enzymatic cleavage by the enzymes trypsin and InA (15) is illustrated in Fig. 3 Upper and Lower, respectively. The all-L peptide was hydrolyzed and inactivated rapidly by trypsin (50% in 20 min at a peptide-to-enzyme weight ratio of 2500: 1) or by InA (50%o in 20 min at a ratio of 200:1). In sharp contrast, the all-D peptide was completely stable to both enzymes, up to a concentration of trypsin 2000 times higher than needed for 50%o inactivation of the L peptide. In addition, experiments in rabbit serum showed that L-cecropin A was 50% degraded in 2 hr, whereas the D enantiomer was much more stable (half-time for loss of activity, 30 hr)." So, it looks like yes.

Methionine racemase

Is there a known genetic mechanism through which a given polypeptide can have its amino acid sequence inverted? For example: A DNA sequence is translated into the sequence: N-MKTSTRFLDGYFPVAANK-C -Mutation occurs- Which leads to the production of: N-MKNAAVPFYGDLFRTSTKM-C The obvious problem is that an inversion will invert the codon sequences (ex. CUU GGA-> AGG UUC = LG-> RU). Is there any known mechanism in nature through it is possible to change something like "AAU UCU GAC" into "GAC UCU AAU"? Furthermore, I've been running blast searches using inverted amino acid sequences of arbitrarily chosen proteins to see if I find any interesting matches, but haven't gotten any expect values lower than 1x10^-3. I've been doing this manually because I am not trained in bioinformatics - do any of you know where I could learn enough to make a program that will automatically go through inverted amino acid sequence blast searches and retrieve the matches with low expect values? Thanks!

Interesting, do you know of any books/papers where I can read more about this? I haven't been able to find anything on endorphin release when popping joints. ~Thanks!

Are you sure you added methanol? Try evaporating a pure methanol solution and see what happens.

That would be a positively charged methyl carbocation. CH3+