How many milligrams of proteins and which amount of work are necessary
to build one gram of human muscle?

Check this site, mate

http://www.ais.org.au/nutrition/FactProtein.htm


To grow muscles, the best way is to have a balance diet.  Protein is
important but is also usually over-emphased.   The primary body fuel
is carbohydrate.  If you do not eat enough carbohydrate, your muscle
will use up the protein as an energy source.  It is very bad for
gaining muscle mass.

In fact, we do not need that much of protein everyday.  The protein
buffer in our body is prettily small.  Eat more CHO instead.  (And
also search for Gycaemic Index)

Good luck.

ChopMan

Most bodybuilding literature recommends 1gram (1000mg) of protein per
pound of lean body mass to sustain an anabolic state.

Therefore if you are 200lbs with 15% bodyfat then your lean body mass
is 170lbs.  Therefor it is recommend you intake (split between 5 to 6
meals a day) 170 grams of protein daily.

The second part of your question is too vague to accurately answer. 
You must first understand that building a muscle or increasing its
size is accomplished only when the cell wall of the muscle cell
thickens.  No additional muscle cells are created.  It does this in
response to workload.  You also have fast and slow twitch muscle
fibers and the relative combination is determined by genetics. 
Sprinters will have much more fast twitch than slow twitch and vice
versa for powerlifters.  So depending on what your combination is will
determine what a specified amount of work will have on muscle growth. 
There are ways to determing how much fast twitch to slow twitch you
have by performing a lifting test.

According to the literature, generally repetitions between 6 to 10 * 3
sets has the most effect in building the most mass in muscle tissue. 
Although everyone is different...for instance the once Mr. Olympia
Dorian Yaters performed only one set per body part and was huge!  I
also know a guy who is about 260 that bench presses with 50 lb
dumbells at a very slow pace.  It really depends on you!

33 grams per pound. The best bet is to have a diet high in protein,
complex carbohydrates such as rice,(stay away from pasta its
proccessed) and on or below 30% of your diet should come from fat such
as olive oil or any plant based fat. Fat is important in keeping your
cells healthy and mobile. Without it every thing stops. If you cut too
much fat your body will hoard every bit you give it and you will never
loose it. Salt is also important. Sodium is neccesary for the
digestion of protein, if you do not take in the appropriate amount of
sodium with the increase of protein you will not be able to grow the
muscle. And, no there is not salt in everthing we eat. Sometimes you
have to make a concious choice to add it to your diet. Halibut is a
good source of salt, shell fish, and of couse: SeaSalt. Keep your
cardio vascular activities up and the oxygen flowing. Get Big!!

Protein is important but is quite overemphasized by the supplement
companies.  If you take in too much protein, you will find yourself
going to the bathroom too often, as your body is excreting it as
waste.  Carbs are probably more important than protein, as well as
monounsaturated fat (olive oil, peanut butter, nuts).

But more importantly, be sure not to overtrain.  Most bodybuilders
copy the routines they find posted in bodybuilding magazines.  Those
routines are for steroid users (steroids allow for longer, more
intense workouts and minimize recovery time).  Long high-set routines
are gross overtraining for a natural bodybuilder.  Keep your workouts
short, but intense and allow your muscles at least a week to heal
before working them again.  Even if you lose soreness in a muscle
group, this just means that the recovery process has ended.  The body
still needs time for muscle growth, so don't hit each muscle as soon
as they seem to "heal".